Antec P180 Review, Part 2: The Whole Nine Yards

Or Everything you ever wanted to know about the P180… including some things you never even dreamed about. It’s the most gi-nor-mongous SPCR review ever. We challenge you to get through it without skipping any of the pages that display some ~14,000 words. Is it worth your time to read? You tell us. NOTE: Postcript about a new updated version added June 15, 2006.

July 4, 2005 by Devon
Cooke

June 15, 2006: POSTSCRIPT V1.1 added to reflect changes made in the case since its original release.

This article is the second part of an extensive review of the P180 that began many weeks ago. Because
of the special status of this case, more time than usual was spent taking measurements
and trying as many configurations as possible to ensure that as much hard data
is available as possible. It is based on over a month of intensive testing.

It is
assumed that the reader has read the previous SPCR articles about this case and has a grasp of its basic features. The article focuses on installation and testing rather than a top-down overview. Please refer to the previous articles as necessary:

• Antec
  P180: A Visual Tour – a detailed examination of features and design, complete with many photos
• Antec P180 Review, Part 1: A Silent System – Ralf Hutter’s ultimate silent build with a Pentium-M system

One issue that came up in the forum discussion of the previous articles
is how SPCR can produce an unbiased review of a case
that Mike Chin, the editor and creator of SPCR, was involved in designing. To address this concern, Mike kept his involvement in the testing and writing to a minimum. I conducted the bulk of the testing, with occasional assistance from Mike Chin.
He remains the editor of all material that is published on the main SPCR web site, however, including this article.

The SPCR-branded P180.

The process of reviewing the P180 began about a month before it was officially
released, when it showed up on the SPCR doorstep in a plain white box…

We couldn’t wait to bring it inside…

Our box was of the scruffy pre-production variety. The retail box is much
more colorful.

PARTS

The lower drive bay contains a small box that holds the larger accessories
and the manual.

A small box of accessories is wedged into the lower drive bay.

In addition to the top spoiler, it contains two sets of drive rails, a warranty
sheet, and the manual.

Many of the important accessories, however, are kept elsewhere. Small accessories
— screws, motherboard standoffs, and spare grommets for the drive bays
— are kept in the accessory box affixed to the back of the upper drive
cage. The remaining drive rails are clipped onto the exterior of the VGA duct,
where they are easily accessible.

The upper drive cage has to be removed to access the accessory box.

A full complement of hardware for installing the motherboard, the drives,
and even extra fans is included.

KEY DESIGN PRINCIPLES & FEATURES

It is worth reiterating this information from the P180 Overview article:

The stated goals for the P180:

• To develop a case incorporating hybrid composite panels with practical
  and effective silencing techniques in a tower-style size that can accept
  a full range of standard PC components; a case that will be quiet even with
  ordinary components, and approach 20 dBA/1m SPL with carefully selected
  components.
• To be a great solution for power users who want ultimate cooling with
  the hottest current desktop PC components, as well as for silencers who
  seek minimal noise, in an understated, modern, elegant style.

There were many principles applied to the P180. The following were central:

• Create separate chambers for better thermal management with less airflow.
• Ensure simple, direct, low-impedance airflow paths.
• Use damping and mechanical decoupling whenever possible to minimize vibration
  transfer.
• Keep any noise at the back of the case as much as possible.
• The front bezel must be transparent for airflow yet prevent direct escape
  paths for noise.
• Use Antec’s unique multi-layer plastic/aluminum composite for the main
  outer panels to eliminate panel vibration.

Core Thermal Design

The positioning of the power supply and the 4-bay hard drive cage in the
separate bottom compartment is a key aspect of the P180’s design. There is
a fan mounting spot — and a supplied 120 x 38 mm 3-speed fan — but
the fan really only needs to be used with a fanless power supply. In normal
use, virtually any fan-cooled PSU should draw enough air from the front vent
of the bottom chamber to keep the hard drives cool. It should also have no
trouble keeping itself cool without ramping up in speed.

From a thermal point of view, this arrangement is highly efficient in that
the airflow of the PSU fan is used not only to cool itself but also the hard
drives. At the same time, the heat of the PSU and hard drives are not adding
to the heat of the CPU and video cards, which are the primary heat producers
in today’s PCs.

A top quality PSU will convert >80% of the AC power it draws into DC power.
The remaining <20% of energy gets wasted as heat inside the power supply,
which is what makes them get hot. If you have an 80% efficiency power supply
and your system needs 200W DC during maximum peaks, then the PSU draws 250W
AC, 50W of which converted to heat in the PSU. Hard drives rarely consume
more than about 10W average in actual operation. If we assume two hard drives,
the total heat in the PSU / HDD chamber or tunnel will not go above 70W. This
is a small amount of heat to be evacuated through this free-flowing air tunnel.

Following this example, in a conventional ATX case where the power supply
is positioned at the top, the 50W of heat from the PSU would be within inches
of the hot CPU, which could easily be producing 100W of heat. The CPU and
PSU would affect each other; both would run hotter, and any thermally controlled
fans (in the PSU, on the CPU heatsink) would tend to ramp up faster. The 20W
from the HDDs would also be added to the overall heat in the case, adding
to the thermal load. With the P180’s separate PSU / HDD chamber, the thermal
load on all the components and on the airflow / cooling system is considerably
reduced.

INSTALLATION

Motherboard

Before anything can be installed, the VGA duct must be removed to give access
to the motherboard tray. Installation of the VGA duct will be covered later,
but the process is quite lengthy.

The VGA duct must be removed before building can begin.

Once the duct is removed, the interior of the P180 is fairly roomy. A standard
ATX motherboard has about 12mm of clearance above the top edge and a couple
of millimeters below. If extra clearance is needed on the top edge (for large,
nonstandard heatsinks), the top fan can be removed to provide an extra 25mm
of clearance. The right edge of the motherboard has 35 mm of clearance, which
makes it easy to slide it into place without pinching a finger.

Installing the motherboard is a simple matter of maneuvering the board into
place and screwing it down. Cables for the front panel are long enough to
reach any point on the motherboard.

Power Supply

The power supply sits in the center of the lower chamber with about an inch
of clearance on every side. Although it is possible to install the power supply
by simply screwing on to the back of the case as usual, it is designed to
be held in place with a specially designed bracket that is lined with a thin
layer of vibration-absorbing silicone. The bracket is placed over the power
supply outside the case and the two are installed together by screwing the
bracket onto the “pedestal” that elevates the power supply in the
center of the channel.

The bracket for the power supply fits quite tightly and needs to be screwed
in from both sides, which means it is necessary to remove the other side panel.
This is the only aspect of installation that requires access to this side
of the case. It is easier to maneuver the power supply into place if the fan
in the duct is removed. The tight fit of the PSU bracket makes it a bit difficult
to position the screws correctly over the corresponding holes. It’s easiest
to loosely attach one screw on each side first before tightening them up.

First, the bracket is placed over the power supply…

…then they are screwed in place together.

Cable Management

Once the power supply is in place, the next step is to determine which cables
are needed, where they are needed, and to route them appropriately around
the case. Unneeded cables can be tucked out of the way in space around the
power supply.

Most of the cables are routed into the upper chamber via a hole with a sliding
plastic cover that can be opened during installation, then closed to fully
separate the two chambers. If the fan in the lower duct is not used, hard
drive cables can be routed directly from the power supply to the lower drive
cage, but if the fan is in use, the cables must be routed through the top
chamber to avoid interfering with the fan.

Once power supply cables are routed into the upper chamber, a sliding
cover seals the holes around the cables to ensure that airflow in the two
chambers remains separate.

The unusual position of the power supply in the P180 means that, depending
on the configuration, there is a chance that the cables will not be long enough.
This is especially true of the ATX motherboard header and auxiliary 12V power
cables, whose headers are often located at the top edge of the motherboard,
away from the power supply. In addition, the position of the VGA duct does
not allow cables to be routed over top of a full size VGA card. This doesn’t
leave many options for neat cable management.

This proved to be the case with one of our test configurations: A Seasonic
S12-430 power supply and an AOpen i915Ga-PLF motherboard. This motherboard
positions the 12V auxiliary connector at the top left of the motherboard —
the worst case scenario. With no other components installed, this connector
barely reached and the cable interfered with the PCI slots. Because our configuration
required a full length VGA card, this was not acceptable. In order to install
the VGA card we had to route the cable in front of the PCIe slot, placing
the cable under tension and ensuring that no other PCI slots could be used.

Connecting the 12V auxiliary connector put the cable under tension and
rendered the PCI slots below the VGA card unusable. (Click photo for larger
image)

A similar problem arose with the 24-pin motherboard header (also 18″).
Although the header is located in the center of the motherboard, its position
along the left edge of the board meant that the cable had to be routed either
over or around the back of the VGA card. The position of the VGA duct made
it impossible to route it over the card, and the cable was too short to go
around. At first it looked like a shorter (and less powerful) VGA card would
have to be used, but a closer inspection revealed a small gap under the VGA
card. A little force and a lot of finesse was necessary to install the VGA
card over top of the the cable (and also the 12V auxiliary cable), but it
did work out in the end.

It’s possible that the issue of cable length could have been dealt with by
leaving the sliding cover between the two chambers open. Because the opening
for the cables is in the center of the cover, the cables are needlessly pushed
out from the back panel of the case as they travel between chambers. Leaving
the sliding cover open could provide an extra inch or two of cable if necessary,
but this would require sealing the gap in some other way (perhaps with duct
tape) in order to preserve the thermal separation between top and bottom chambers.

The 24-pin motherboard cable had to be routed under the VGA card
to get it to fit properly.

Correctly routing the cables in the P180 is a time-consuming task. Because
the cables come up from the bottom of the case, it’s easy to create a thick,
airflow-restricting nest of cables on the bottom of the upper chamber. I found
the floppy bay (unused during testing) an excellent place to hide extra cable
slack.

INSTALLATION (continued)

VGA Duct

Note: The VGA duct has been dropped in the latest revision of the case. Read more in POSTSCRIPT V1.1

The VGA duct consists of two parts: The duct itself, and a plastic sleeve
at the intake that keeps the duct in position. The duct can be slid back and
forth about 1.5″ to accommodate video cards of varying lengths. As mentioned
above, the duct must be removed before a motherboard can be installed in the
case. This inconvenience would be minor if it were just the duct that had
to be removed. However, the sleeve for the duct is screwed to the back of
the case directly above the PCI slots, which means it must also be removed
before any expansion cards can be installed.

The sleeve for the VGA duct must be removed to install a PCI card.

The VGA duct is attached to a bracket on the bottom of the main chamber with
two wide-head screws that are recessed about quarter inch below the surface
of the duct. This position is awkward when installing the duct and makes it
hard to see where the screws need to go. Considering that the duct must be
removed to access the motherboard, it would be nice to replace these screws
with thumbscrews. Unfortunately, the screws use a finer thread than the one
used on most thumbscrews and the recessed position of the holes would interfere
the large head of a thumbscrew. The use of a magnetic-head screwdriver is
recommended.

Once these two screws are removed, the duct slides out sideways, giving access
to the motherboard. If the sleeve needs to be removed, it can now be unscrewed
from the back of the case. The sleeve is held on by four screws that screw
directly into the plastic. This method of mounting is not especially durable,
and the sleeve showed visible signs of wear and tear after the dozen or more
times it was installed during testing.

The duct is held in place by two screws that are slightly recessed
below the surface of the duct.

Because the duct is designed to be adjustable, the fit between the intake
sleeve and the duct itself is not as tight as it could be, especially at full
extension. This makes it a possible source of vibration noise, especially
if a fan is installed in the duct.

Hard Drive Cages

In contrast with the installation for the VGA duct, the installation of the
drives is simple and user-friendly. Both drive cages are removable and slide
out smoothly on soft plastic rails. Both feature a pull ring for ease of removal
and are secured to the chassis by a single, well-located thumbscrew. The pull
rings can be clipped down when it’s not in use to prevent it from rattling
against the side of the drive cage.

Installation differs slightly depending on which cage is used. The upper
cage uses drive caddies that are separate from the cage itself, but drives
in the lower cage must be screwed directly in place. No matter which cage
is used, the drives are always isolated from the drive cage using soft silicone
grommets. The matching drive screws have wider flanges and are longer than
usual.

The top drive cage uses caddies that are screwed on to the bottom of the
drives before they are clipped into place.

If four drives are used in the lower drive cage, the orientation of the drives
becomes important. The rearmost position in the cage only allows a drive to
be installed with the top of the drive facing out, meaning that any neighboring
drives also need to be installed in this orientation. With fewer than four
drives, this issue is irrelevant because there is no need for the rearmost
position to be used, but some extra care is needed when filling the cage to
capacity.

Actually screwing the drives in place is a simple matter. It’s easy to turn the large-flanged screws
in by hand, which dispenses with the need for a screwdriver. Once
the drives are firmly in place, all that needs to be done is to slide the
drive cage into place. The trickiest part is making sure the cables are properly
connected, since it’s more difficult to install cables once the cage is in
place. This is especially true of the lower drive cage. It’s probably a good
idea to route the cables before installing the drives and plug them in while
the drive cage is halfway out and the duct fan removed.

The correct way to mount the grommets: Thicker side against the drive on
the bottom, and thinner side against the drive on top.
It makes sense when you examine the grommets. It ensures a cushier ride for
the HDD.

FANS

The simplest way to set up the fans in the P180 is to plug the stock
fans into a spare Molex connector and leave it at that. However, most users
will want to remove the thick 38mm fan in the power supply chamber during
installation, while others will want to install an extra fan in the front
or in the VGA duct.

The PSU chamberfan is attached to a plastic bracket that allows it to be
removed without unscrewing it. It is quite simple to remove, but the method
is not obvious. Unclip it by pressing the lever into
the case while pulling the whole unit out. Reinstall by reversing the process.
It’s easiest to use your fingers to grip the inside of the fan and your thumb
to press the lever.

Fully installed. Note the cable nest in the upper chamber.
Click to download a movie clip of the fan installation (696 KB).

An empty fan bracket comes installed at the front of the case for those who
want to install a front fan. The installation process is the same as for the
fan in the PSU duct.

120mm fans are installed using a bracket that clips easily into place.

The 38mm PSU chamber fan installed on the fan bracket and ready to be clipped
into place.

Unlike the 120mm fans, installing the 80mm fan in the VGA duct is a lengthy
process. The mounting holes for the fan are inside the VGA duct,
which means it must be fully disassembled before the fan can be installed.
The VGA duct consists of two halves that are held together by five screws.
Like the sleeve for the duct, the screws mate with the plastic frame and the same
issue of durability is present.

The mounting holes for the 80mm fan are located inside the VGA duct.

Once the duct is disassembled, it’s a simple matter to screw in an 80mm fan
using the included fan screws. The choice of fan is important because it protrudes
above the surface of the duct. The standard 25mm thick fan that we tried first
made it impossible to reinstall the duct with our choice of VGA card —
our card was too tall to provide the clearance necessary. Every
high performance VGA card in the SPCR lab was the same height (about 5mm above
the top edge of the PCI bracket), so a 20mm thick fan was used instead.

The 20mm fan allowed the duct to be properly installed, but the fan was flush
against the VGA card. Reversing the direction of the fan (making the duct
an exhaust instead of an intake) put the fan blades in contact with the VGA
card, making it unsafe to use the fan in this configuration.

Fan Characteristics

All of the fans used during testing, including the stock Antec fans, were
also tested individually outside the P180 so they could be compared to other
known fans.

P180: Fan Characteristics
Fan	Setting	CFM	SPL
Antec 120 x 25mm TriCool	H	75	39 dBA/1m
	M	47	31 dBA/1m
	L	28	20 dBA/1m
Antec 120 x 38mm TriCool	H	64	30 dBA/1m
	M	55	27 dBA/1m
	L	39	23 dBA/1m
Nexus 120 x 25mm	12V	42	23 dBA/1m
	7V	25	18 dBA/1m
	5V	16	<17 dBA/1m
Antec 80 x 20mm	12V	17	22 dBA/1m
	7V	9	<17 dBA/1m
	5V	4	<17 dBA/1m

The two 120mm TriCool models are quite different in character. The range
of the thinner 25mm fan is quite amazing. This fan can be a monster or a model
depending on how it is set. Of interest to the SPCR audience is the Low setting,
which blows a respectable 28 CFM at an even more respectable 20 dBA/1m. The
noise signature is quite smooth at this level, perhaps on par with the Nexus
at 12V. Although the Nexus is slightly quieter for the amount of airflow it
produces, the TriCool performs very well for a stock fan.

Although the thinner TriCool fans don’t vibrate any more than usual, it is worth
pointing out that, unlike in some other Antec cases, they are hard-mounted with screws. Soft mounting the fan with E.A.R. grommets produced
an audible drop in the overall system noise. It measured only a decibel or so, but it was subjectively significant in a quiet system.

The 120x38mm TriCool has less range and is louder at the low end, though
it is still far from loud. However, the character of the noise is dirtier.
This fan has a low growl or rumble that makes is more immediately identifiable
than its thinner cousin. It also vibrates a lot, which may explain the rumbling
in its noise character. It is probably not acceptable for a demanding silent
PC enthusiast.

The 80x20mm fan provided by Antec for the VGA duct is quite impressive, especially
for a thin, low profile fan. Its noise character is smooth and fairly low
pitched, and its maximum SPL of 22 dBA/1m is very modest. This fan
is not normally included with the P180. It has no identifying markings whatsoever except the Antec label on the hub.

Fan Recordings

MP3:
120 x 25mm Antec TriCool, 10s Low, 5s Medium, 5s High: 20-31-39 dBA/1m

MP3
120 x 38mm Antec TriCool, 10s Low, 5s Medium, 5s High: 23-27-30 dBA/1m

MP3:
120 x 25mm Nexus, 8.8V: 35 CFM / 19 dBA/1m
MP3: 120 x 25mm
Nexus, 12V: 41 CFM / 23 dBA/1m

MP3:
80 x 20mm Antec, 12V: 22 dBA/1m

HOW TO LISTEN & COMPARE These recordings were made with a high resolution studio quality digital recording system. The microphone was 3″ from the edge of the fan frame at a 45° angle, facing the intake side of the fan to avoid direct wind noise. The ambient noise during all recordings was 18 dBA or lower. It is best to download the sound files to your computer before listening. To set the volume to a realistic level (similar to the original), try playing this Nexus 92mm case fan @ 5V (<17 dBA/1m) recording and set the volume so that it is barely audible. Then don’t reset the volume and play the other sound files. Of course, all tone controls and other effects should be turned off or set to neutral. For full details on how to calibrate your sound system playback level to get the most valid listening comparison, please see the yellow text box entitled Listen to the Fans on page four of the article SPCR’s Test / Sound Lab: A Short Tour.

THERMAL & ACOUSTIC TESTING

Two systems were assembled in P180 samples for testing:

1) A very hot, powerful system based around an Intel 660 overclocked
to 3.8 GHz, an nVidia 6800GT video card, and a Western Digital Raptor 74G drive.
This is definitely a high-end, high power gaming system that can only be significantly
bettered by a dual VGA card setup. With a lack of care and planning, such a
system could easily measure 40 dBA/1m. Our task here was find the most efficient,
quietest method of cooling this hot system in the P180 case.

2) A mid-thermal but quite powerful system based around an AMD
Athlon 64 3500+ (Winchester core), nVidia 6600GT video card, and a dual Maxtor DiamondMax 10
RAID storage setup. This is probably as powerful a system as most silence-oriented
readers will want to build. The rule of thumb is that the hotter the components,
the harder it is to keep them running well quietly.

Together with Ralf Hutter’s work in Part One, our review covers the P180 with three different classes of systems:

• a low-thermal as-quiet-as-possible system,
• a mid-thermal powerful system,
• a hot gaming system.

This should provide users with a comprehensive appreciation of the P180’s performance and potential.

Testing Tools

• CPUBurn
  processor stress software
• Prime95
  processor stress software
• Futuremark
  3DMark05 VGA benchmark
• SpeedFan
  4.24 software to show CPU temperature
• ThrottleWatch
  2.01 to monitor CPU throttling
• Steinberg Wavelab
  5 recording and analysis software
• Seasonic
  Power Angel to measure AC power draw
• T.H.E. KP-6M
  reference omni microphone
• M-Audio
  Tampa mic preamp
• M-Audio
  Firewire 410 external digital sound interface
• B&K 2203
  sound level meter

SYSTEM ONE: THE HOT POTATO

System Components

• • AOpen i915Ga-PLF motherboard
  • Intel 660 3.6 GHz processor, rated 115W TDP by Intel with a calculated
    Maximum
    Power of 148W; overclocked to 3.8 GHz
  • 1 GB OCZ Gold PC4000 DDR SDRAM (2 x 512 MB sticks)
  • Scythe Ninja CPU heatsink
  • AOpen Aeolus 6800GT DVD256MV VGA card, thanks to AOpen
  • Western Digital Raptor 74GB hard drive
  • Samsung CD-RW drive
  • Seasonic S12-430 430W power supply

Fully installed. Note the cable nest in the upper chamber.
It’s especially bad because the lower drive bay is completely full. (Click
for a larger image)

Ambient temperature during testing was usually 21°C, rising occasionally
to 22°C. Ambient noise level was 18 dBA/1m. EIST (SpeedStep) was enabled,
as was the PowerMaster feature of the AOpen motherboard. It provided a 5% overclock at full load and underclocked the processor down to 2.56 GHz at idle, which is reflected in the idle temperatures and AC power.

Configuration 1

The starting configuration was as follows:

1. The CPU was overclocked by 5% under load. The FSB was run at 210
   MHz, bringing the CPU frequency up to 3.8 GHz, on par with the top of the
   line Intel 670 processor. The system remained completely stable under this
   modest overclock.
2. The built-in fan on the VGA card was undervolted to 8.25V, the level
   at which the fan noise dropped to the level of the other fans.
3. The 120 x 38mm fan in the PSU chamber was removed on the assumption
   that the airflow provided by the Seasonic S12 would be enough to cool the
   Raptor installed in the lower drive cage.
4. The upper drive cage and front fan holder were removed entirely to
   minimize the airflow impedance near the intake.
5. The VGA duct was also removed in hopes that the airflow around the
   VGA card would already be sufficient.
6. Airflow in the upper chamber was provided by the the rear Antec TriCool
   fan, set on Low.
7. The top fan was left installed but unplugged, and the top vent was covered
   by placing a thick notebook over the hole.
8. No fan was used on the Ninja heatsink in hopes that the airflow of
   the twin TriCool fans would be enough to allow fanless operation.

Firing up CPUBurn for the first time proved a bit disappointing. CPU temperature
shot up to 74°C, where throttling kicked in to prevent the temperature
from rising any higher. To reduce the temperature, as much impedance as possible
near the intake was removed: The front door was opened and both the filter
and the filter door removed. Even the VGA duct was sealed up to address the
possibility that air was uselessly being pulled though and exhausted without
doing anything.

Unfortunately, none of these adjustments reduced temperatures enough to prevent the CPU
from throttling, although the changes in the amount of throttling showed that
these slight differences caused equally slight changes in airflow. The most
significant factor proved to be whether or not the front door was open, which
reduced temperatures by 2°C but audibly worsened the system noise somewhat more than the measured 2 dBA/1m would indicate.

Configuration 2

The next step was to unblock the top vent and turn on the second exhaust
fan, set to Low. Both the 120mm fans were blowing out, as per Antec’s
default setup. All the other details were left the same as in Configuration
1. Unfortunately, the additional fan seemed to produce no significant benefit;
the CPU continued to throttle under full load, even after the opening the
door and removing the filter.

In spite of the additional fan and the unblocking of a potential noise path,
the level of noise was very similar to the first configuration. The SPL measurement
bore out this conclusion: They measured the same.

Configuration 3

The ineffectiveness of the second fan suggested that there might be a bottleneck
in the airflow, so a Nexus 120mm fan was installed in the front fan bay.
The rest of the system was the same as in Configuration 1. Like the previous
two experiments, this one also proved ineffective. In fact, the 2 dBA/1m increase
in system noise made this a particularly poor attempt at preventing the CPU
from throttling.

Configuration 4

At this point, we began to give up on being able to run our processor heatsink fanlessly.
However, one final option, inspired by Intel’s TAC duct, remained to be tried: Go back to Configuration 1, and unblock the top vent
without turning on the fan. This made the top vent the primary intake for the back panel fan, and this air would be forced to flow through the huge Ninja HS, effectively
lowering the ambient temperature around it. The disadvantage of this configuration
would be that less air would be drawn through the front intake. System and VGA temperatures
were watched closely to ensure they didn’t rise to unhealthy levels.

This configuration takes advantage of the large size of the Ninja heatsink.
Because the Ninja fills almost the entire width of the case, air drawn from
the top vent by the rear fan is forced to travel over the fins of the
heatsink. A lower profile heatsink would benefit less from this configuration,
and a great deal of air would be needlessly sucked through the case without
ever cooling anything.

This experiments proved to be a success. With the CPU
under load, the temperature stabilized at 65°C — warm, but not high
enough to start throttling. Surprisingly, the system and GPU temperatures
did not seem to be affected much. The GPU even dropped a degree or two in
this configuration.

The level of noise in this configuration was almost identical to the noise
in Configuration 1. Surprisingly, blocking or unblocking the top vent made
very little audible and no measurable difference. In fact, I personally preferred
the sound of the case with the top vent open, as it sounded slightly less
“choked” and less resonant. (Editor’s Note: I and
another innocent bystander called in to witness also preferred the sound with
the top blow hole open for the same reasons.)

Configuration 5

The final configuration was the obvious one: Add a Nexus 120 fan at 12V
to the Ninja heatsink in Configuration 4. It was set up to blow
through the fins towards the rear case fan, creating a push-pull airflow effect
across the heatsink. The CPU temperature at full load dropped dramatically
to a mere 55°C, while the noise was similar to Configuration 3. The ten
degree drop in temperature is substantial enough that most gamers would probably be
willing to pay the acoustic price.

Acoustic Recordings and Summary of Configurations

MP3:
P180 “Hot Potato” Configuration 4: 25 dBA/1m

MP3:
P180 “Hot Potato” Configuration 4, door open: 26 dBA/1m

MP3:
P180 “Hot Potato” Configuration 3 (Nexus 120mm installed in front bay): 27 dBA/1m

Antec P180 / Intel High End System Test Summary (Stressed by 2 x CPUBurn)
Configuration	CPU Temp.	SPL
1	74°C*	25 dBA/1m
2	72°C*	26 dBA/1m
3	72°C*	27 dBA/1m
4	65°C	25 dBA/1m
5	55°C	27 dBA/1m
*CPU Throttling occurred in these configurations.  >> AC Power Draw at full load: 236W <<

IMPACT OF VIDEO CARD HEAT

The effectiveness of opening up the top hole suggested that the difficulty
with CPU cooling was due primarily to the hot NVidia 6800GT sitting right
under the CPU. To test this theory, a lower powered VGA card — an
AOpen Aeolus 6600GT — was installed in place of the 6800GT. Configurations
1 (top vent sealed, back 120mm fan on low) and 2 (both 120mm fans on low)
were then tested again with this slight system change.

Intel High End System: 6800GT vs. 6600GT (Stressed by 2 x CPUBurn)
Configuration	VGA	CPU Temp.
1	6600GT	63°C
	6800GT	74°C*
2	6600GT	60°C
	6800GT	72°C*
*CPU Throttling occurred in these configurations.   AC Power Draw at full load: >> w/ 6800GT: 236W << >> w/ 6600GT: 210W <<

This time, the CPU did not throttle. In fact, with the top vent sealed it
stabilized around 63°C — a 10°C difference compared with the
same configuration when the 6800GT card was in place! This is a substantial
difference.

The total difference in system heat can be estimated by examining the difference
in AC power draw between the two systems: With the 6800GT, AC draw under load
was 236W versus 210W with the 6600GT. At this power level, the Seasonic S12-430
is ~80% efficient, meaning that the actual difference in heat is roughly 21W.
This is a huge difference for a GPU at idle.

Any nVidia 6800GT video card is a challenge to cool quietly.

VGA COOLING

Once the best means of cooling the CPU quietly was established, further tweaking
could be done to improve the the temperature in the rest of the case, especially
around the video card. The 6800GT card was returned to the system, and Configuration
4 was kept as the baseline for experimentation because it could cool the
CPU adequately, and do it more quietly than Configuration 5, the only configuration
that was cooler.

1. The CPU was overclocked by 5% under load. The FSB was run at 210
   MHz, bringing the CPU frequency up to 3.8 GHz, on par with the top of the
   line Intel 670 processor. The system remained completely stable under this
   modest overclock.
2. The built-in fan on the VGA card was undervolted to 8.25V, the level
   at which the fan noise dropped to the level of the other fans.
3. The 120 x 38mm fan in the PSU chamberwas removed on the assumption
   that the airflow provided by the Seasonic S12 would be enough to cool the
   Raptor installed in the lower drive cage.
4. The upper drive cage and front fan holder were removed entirely to
   minimize the airflow impedance near the intake.
5. The VGA duct was also removed in hopes that the airflow around the
   VGA card would already be sufficient.
6. Airflow in the upper chamber was provided by the the rear Antec TriCool
   fan, set on Low.
7. The top fan was left installed but unplugged, and the top vent was uncovered
   to ensure optimal CPU cooling
8. No fan was used on the Ninja heatsink, thanks to our experience in
   the previous section.

Because we do not have a reliable, repeatable way to load the VGA card, thermal
comparisons were done with the system at idle. VGA temperatures were read
from the NVidia driver utility that is installed in Windows Display Properties.
Keep in mind that the VGA fan was undervolted to 8.25V throughout testing,
so the temperatures are higher than they would be if the card was run as intended.

VGA Duct Configurations

Because of compatibility issues (see the section above on installing the
VGA duct), a low profile Antec 80×20 mm fan (tested in the above section on
Fan Characteristics) was installed in the VGA duct of the P180. The fan was
undervolted to 10.8V using a Zalman Fanmate, with the expectation that, if
all went well, further undervolting could be done.

As mentioned before, this fan is quite impressive, especially for a thin,
low profile fan — at least while it is spinning in free air. Unfortunately,
installing it in the VGA duct ruins it completely. At full tilt, the duct
greatly amplifies the volume of the fan and also accentuates a sharp, unpleasant
buzz. This is entirely the fault of the duct, as it is prone to resonating
and amplifying the vibrations produced by the fan. Both the duct material
as well as the air in the duct contribute to the resonance. At 7V and below,
the nasty effects of the duct are much subdued, but so is airflow and cooling.

In fact, the sonic effect of the duct was so noticeable that it was worth testing
the duct outside of the P180 case. The results were quite dramatic.

80 x 20mm Antec Fan Characteristics
Position	Setting	SPL
Free Air	12V	22 dBA/1m
	7V	<17 dBA/1m
	5V	<17 dBA/1m
in VGA duct	12V	30 dBA/1m
	7V	21 dBA/1m
	5V	18 dBA/1m

The VGA duct was tested in the case in a number of different configurations, summarized in the table below:

P180 VGA Duct
Duct	GPU Temp. (idle)	SPL
Not installed (Configuration 4)	69°C	25 dBA/1m
Installed	67°C	27 dBA/1m
Installed at full extension (fan ~1.5″ deeper into the case)	69°C	27 dBA/1m
Installed with fan reversed (exhaust instead of intake)	71°C	27 dBA/1m
Not installed (VGA card fan @ 12V)	57°C	29 dBA/1m

As expected, the GPU temperature went down with the duct installed. However,
it’s quite surprising how small the decrease was. The biggest (and only) improvement
was a measly 2°C — perhaps not even statistically significant. Some
configurations even made the temperature rise, indicating that the duct was
disrupting airflow around the card.

The minimal effect of the VGA duct may have something to do with the design
of the cooling system on our test VGA card. Like many other high-end cards
on the market, the Aeolus 6800GT uses a duct style heatsink that blows air
across the card. This means that the bulk of the heatsink is actually covered
up. The surface area that can benefit directly from the additional airflow
of the VGA duct is minimal. The VGA duct is probably most effective when the
VGA card has large, open heatsinks, such as AOpen’s
new passively cooled cards.

The smooth heatsink on the VGA card is designed to be be used as a duct
with the stock fan, and is ineffective when used with the external duct fan.

Positioning the duct to blow across the back half of the card — where
the exposed heatsink fins might benefit more from increased airflow —
did not have the desired effect; instead the GPU temperature rose. Reversing
the direction of the duct fan was even worse. Not only was there a danger
of contact between the spinning fan blades and the VGA card, but temperatures
were worse then with the duct removed entirely.

The minimal cooling benefit of the VGA duct in our configuration was not
worth the 2-3 dBA/1m increase in system noise. If the GPU temperature becomes
excessive and requires an increase in noise, it is much more noise-efficient
to simply increase the voltage of the fan on the VGA card. Running the fan
at full speed did sound louder than with the duct installed, but here the
drop in temperature was 10 degrees, not two.

MP3:
P180 “Hot Potato” Configuration 4 (no duct installed): 25 dBA/1m

MP3:
P180 “Hot Potato” with VGA duct installed: 27 dBA/1m

MP3:
P180 “Hot Potato” with VGA fan at full speed, no duct installed:
29 dBA/1m

Front Fan Configurations

An alternate
method of cooling the VGA card needed to be found, preferably not increasing
the voltage of the stock fan. With high hopes, the Nexus 120mm fan was reinstalled
in the front fan bay, this time to gauge its effect on the VGA card. Testing
was done in combination with the VGA duct (with the Antec 80x20mm fan at 10.8V
running in it) in hopes that the two together might achieve better results
than either could singly.

P180: Front Fan
Front Fan Voltage	VGA Duct	CPU	GPU Temp.	SPL
no front fan	Removed	65°C	67°C	25 dBA/1m
12V	Installed	66°C	65°C	29 dBA/1m
12V	Removed	70°C*	65°C	28 dBA/1m
5V	Installed	67°C	66°C	27 dBA/1m
5V	Removed	69°C	69°C	25 dBA/1m
The processor was under 100% load with 2xCPUBurn * CPU Throttling occurred in this configuration.

At 5V, the Nexus was insignificant, both thermally and acoustically. A slight
increase in CPU temperature indicated that more heat from the VGA card was
finding its way across the fins of the CPU heatsink.

At 12V, the effect on temperatures was similarly unimpressive, at least while
the VGA duct was installed. Furthermore, the volume of the system noise increased
by 2 dBA/1m — a needless increase.

However, with the VGA duct removed, the GPU temperature actually dropped
slightly, perhaps in response to the increase in circulation over the top
(trace) side of the card. The 65°C idle for the GPU without the VGA duct installed
was the lowest idle temperature for the GPU during all testing. Although the
SPL for the Nexus alone measured slightly higher than the VGA duct alone,
subjectively the Nexus 120 fan sounded much better. At 12V, the Nexus’ main contribution to the system
noise is an increase in turbulence noise and a low, smooth hum. This is considerably
more pleasant than the droning buzz of the resonating fan in
the VGA duct.

The downside of running the 12V Nexus without the VGA duct is a 5°C increase
in CPU temperature, enough to force the CPU to start throttling.

The increase in CPU temperature was enough to convince us that a better temperature
for the GPU could not be easily achieved with the 6800GT without compromising
system noise. The 69°C idle is high, but acceptable. According the NVidia
driver, the GPU core can hit 127°C before it throttles itself back, which
still provides a 50°C cushion. Some minor graphical glitches were detected
while running 3DMark05, but Doom III, well known for its steep system requirements,
was quite playable with all graphics options enabled. A hardcore gamer would
no doubt be happier running the VGA fan at full speed and paying the acoustic
price, but it was decided that the borderline thermal performance was worth
the acoustic benefit for our test.

In the end, it seems likely that for the best cooling and lowest noise, a
capable, massive aftermarket heatsink needs to be installed on this hot video
card, perhaps combined with a low speed fan in the VGA duct. There was not
enough time to fully explore this hypothesis.

HARD DRIVE MOUNTING / COOLING

One of the major design features of the P180 is mounting system for the hard
drives, which are decoupled from the chassis with soft silicone
grommets. In combination with the multi-ply construction of the case, this
is intended to address on of the most difficult-to-eliminate sources of noise
in a typical PC: Hard drive resonance. To test the effectiveness of the grommets,
the
resonant aluminum box that we usually use to test hard drives was pressed
into service.

Drive vibration is assessed by ranking the resonance produced by the drive
on a ten point scale when it is placed on this box.

A number of reference drives were installed in the lower drive cage, and
the entire cage was placed on the vibration box. The resonance of the whole
cage was then assessed on a ten point scale according to our usual standard
for vibration. In most cases, a ranking of 7 or above indicates that vibration
is unlikely to be a major source of noise. Most 3.5″ drives fall in the
range of 4-6, while most 2.5″ notebook drives rank 8 or 9.

P180: Drive Mounting System
Drive	Vibration Rating (1-10, 10=No Vibration)
	Bare Drive	in Drive Cage
Seagate Barracuda IV	6	9
Maxtor DiamondMax 10 (sample 1)	2	7
Maxtor DiamondMax 10 (sample 2)	3	6
2 x Maxtor DiamondMax 10 (mounted together)	1?	5
Western Digital Raptor Seagate Barracuda IV Hitachi Deskstar 7K250 Western Digital Caviar	1?	6

The reduction in vibration transfer when a drive is installed in the P180
drive cage is impressive across the board. The Barracuda IV — fairly
good when it comes to vibration — is damped almost completely.

The two DiamondMax 10 samples are the most vibration-prone drives in our
lab and represent a sizable challenge. Installed in the drive cage, vibration
was reduced to good-to-excellent levels. For some reason, the worse of the
two drives benefited considerably more from the soft mounting than its lower-vibration
twin.

The two DiamondMax 10 drives were then installed together. The “5”
rating that was measured is about average for a single drive and is better
than either of the drives individually.

PSU/HDD Cooling With Four Hard Drives

Of course, the real test of the drive mounting system is to actually install
some drives in the P180 and see how much vibration noise occurs. The results
of the vibration testing suggested that a single drive wouldn’t be a challenge
to silence, and the system drive did not get unduly warm during the previous
bout of testing. All this suggested that a more challenging system was needed
to test the drive capabilities of the P180.

Three drives — a Seagate Barracuda IV, a Hitachi Deskstar 7K250 and
a Western Digital Caviar — were added to the base system for a total
of four drives. In all other respects, this build was the same as
Configuration 4, the reference system that was used for testing the VGA
duct. The cage with these drives was also tested on the vibration test box,
as shown in the photo below. The resulting hum box resonating under the four
drives cycled in volume, but was only about as loud as a single bare Seagate
Barracuda IV at its peak.

The heavily loaded drive cage being tested for vibration.

This 4-drive package was used in the P180 to test different cooling options
in the PSU / HDD chamber. It represents the most restrictive airflow impedance
and the greatest amount of drive heat (short of multi-platter, >10k RPM
SCSI drives) that can be added to the lower chamber. Hot Potato Configuration
4 was used, and the power supply was a stock Seasonic S12-430 (latest version
with Adda ball bearing fan). The system was left to idle with each cooling
setup until HDD temperatures stabilized, typically an hour and a half or more.
For simplicity, only the data from the Deskstar has been listed in the table
below, but all drives behaved similarly.

P180 PSU/ HDD Chamber Cooling
Setup	Deskstar Temp.	SPL
1	46°C	26 dBA/1m
2	43°C	26 dBA/1m
3	37°C	28 dBA/1m

PSU/HDD Setup 1

The S12 PSU’s fan was the sole source of airflow in the PSU chamber.
All of the drive temperatures stabilized in the mid-to-high 40’s — a
bit high, especially in a system with heavy drive usage. However, noise was
impressively low, rising only a one decibel above the same configuration
with a single drive. No vibration or resonance could be heard, meaning that
no further drive vibration dampening is necessary.

PSU/HDD Setup 2

The rear panel exhaust vents that surround the power supply were taped
up. This prevented the PSU fan from drawing any air in from the back, forcing
air to be pulled from the front vent and through the spaces between the drives.

This configuration brought most of the drive temperatures into the low 40’s.
One even dipped to 38°C. These temperatures are perfectly acceptable in
a quiet system, although someone running a home server might prefer a larger
margin for error.

The decrease in HDD temperature was achieved without increasing the total
system noise. This remained true even when the system was placed under load,
the S12-430 had no problem exhausting the ~25W of heat produced by the drives,
and its fan never ramped up audibly.

The air vents around the power supply were sealed with tape to ensure that
the power supply drew its air through the front intake.

Note that sealing the exhaust vents will have even greater effect when a

PSU with a faster fan is used. In fact, when the power supply was swapped
out for a Seasonic Super Silencer 400W, hard drive temperatures decreased
under heavy load with CPUBurn (power draw of ~240W AC). The Super Silencer
400W fan ramped up somewhat more than the S12 under the same load. As a result,
airflow across the HDDs also increased, thus dropping their temps by 3~4°C.

PSU/HDD Setup 3

If the system used for data-critical applications, the lowest drive temperatures
may be desired. Employing a 120mm fan is likely to provide the best cooling
for both PSU and HDDs.

The supplied 120 x 38mm Antec TriCool fan was duly installed in the center
position and set to low speed. The improvement in drive temperatures soon
became apparent; they dropped into the mid-thirties, and noise rose only slightly,
although the growl of the fan worsened the quality of the noise a little.
Replacing the chamberfan with a Nexus 120 or one of the 120 x 25mm Antec
TriCool fans set on low would probably drop HDD temperature similarly while
minimizing the impact on system noise.

Sealing the rear vents had no effect on drive temperatures when the lower
chamber fan was installed; the pressure of the thick TriCool fan was enough
to force the extra airflow through the power supply when the rear vents were
blocked. There was no apparent impact on PSU fan, which was not ramping up
audibly anyway, but we can safely assume its internal operating temperature
must also have dropped a bit.

Split HDD Setup

Perhaps the best method of keeping four hard drives (and the PSU) cool is
to separate the drives. There is no shortage of drive bays in the P180, and
it is easy to move a pair of drives to the upper drive cage to provide more
breathing space in the lower drive cage. To test the effectiveness of the
upper drive cage, the system drive (a Raptor) was tried in the upper drive
cage.

P180: Upper Drive Cage
Drive Condition	Raptor Temp.
Lower Cage (no fan, rear vents unblocked)	41°C
Upper Cage	41°C

With no additional cooling, there is very little difference between the two
drive cages; the temperature stabilized at 41°C wherever the drive was
installed. Noise levels were the same regardless of which drive cage was used.
Neither CPU nor GPU temperature seemed to be affected by the additional airflow
impedance produced by the hard drive in the upper cage. If the fan in the
PSU chamber is not used, there appears to be very little difference, acoustic
or thermal, between the two drive cages. Installing the lower chamber fan
or taping up the vents around the PSU makes the lower drive cage a cooler
place to install drives.

CASE COMPARISON: VS. ANTEC SLK3000B

All of the above testing showed that the best low-noise, good cooling configuration for the
test system was still Configuration 4. This “best possible”
configuration was compared against a similar “best possible” system built
in one of the best conventional cases we know of, the Antec SLK3000B. Short of an SLI-based
system, our test components run hotter than almost
any other desktop PC setup.

You may recall that Ralf Hutter
gave the SLK3000B a favorable review when it first appeared. For the uninitiated,
a couple of photos for reference:

The SLK3000B side panel is equipped with a CPU vent as well as a VGA vent.

Clean steel mid-tower ATX layout with a TriCool 120×25 fan on back panel
and free-breathing 120mm front vent.

The Comparison System

The system installed in the SLK3000B was the same system used in the P180.
Although this meant side-by-side comparisons were impossible, it was the best
way of ensuring that thermal data between the two systems would be comparable.
Variations in temperature and noise can only be attributed to differences
between the two cases. Small differences may be attributed to statistical
variance, but large differences should reflect the advantage of one system
over the other.

The number and kind of fans in each system were always kept identical to
each other. In both cases, an Antec TriCool fan set to Low was used to exhaust
system heat, and the VGA card was always undervolted to 8.25V.

Various configurations of power supplies, hard drives, and CPU fans were
tested, but comparisons were done with the two systems configured as closely
as possible. The most serious variation is the position of the power supply
fan, but but this difference is inherent and will be apparent no matter what system is installed.

For those who forget what was in the P180 system, here are the components
used for the test:

System Components

• AOpen i915Ga-PLF motherboard
• Intel 660 3.6 GHz processor, rated 115W TDP by Intel with a calculated
  Maximum
  Power of 148W; overclocked to 3.8 GHz
• 1 GB OCZ Gold PC4000 DDR SDRAM (2 x 512 MB sticks)
• Scythe Ninja CPU heatsink
• AOpen Aeolus 6800GT DVD256MV VGA card, thanks to AOpen
• Western Digital Raptor 74GB hard drive
• Samsung CD-RW drive
• Seasonic S12-430 430W power supply

Here is the interior of the SLK3000B with all those components installed.

The wiring was actually much less restrictive to airflow than this
photo might suggest.

Comparison One

CPU Cooling

The two cases were similar in the level of CPU cooling they were able
to achieve. The CPU temperature did not vary by more than a degree between
the two systems. These differences are most likely statistically meaningless,
so for practical purposes the airflow around the CPU can be considered identical.

Both cases benefited from an extra intake vent for the CPU: The top 120mm
vent on the P180 and the side vent on the SLK3000B. The latter also had the
benefit of the fan in the S12 PSU, but it remained spinning very slowly throughout
the stress testing and probably did not help much.

VGA Cooling

Regardless of how the VGA duct was configured, the P180 could not quite match
the VGA temperatures of the same card in the SLK3000B, which were typically
5~6°C lower at idle. It’s possible that airflow in the VGA area of the
P180 was lower because the rear fan could draw fresh air in through the top
vent eliminating the VGA card from the airflow path in the case. This result
seems a clear indication that the open vent in the side panel of the SLK3000B
is slightly better than the VGA duct in the P180 in helping to cool the VGA
card.

P180 intake vent on left seems a more restrictive than the SLK3000B intake on right: Could this explain the somewhat higher VGA temps in the P180?

Note: The load temperatures for the GPU are not that reliable because
the temperature could not be monitored simultaneously with our GPU “stress”
software, 3DMark05. The temperature listed in the above table corresponds
to the highest temperature seen on the driver window as the desktop flashed
briefly between different benchmarks. Needless to say, this technique does
not lend itself to repeatable, reliable data, but it is the best that could
be done given that there was no way of logging the temperatures during the
benchmark.

Noise

With the same number of noise sources in the two case, roughly the
same SPL was measured. Turning the Nexus fan on the heatsink on or off made
a 2 dBA/1m difference in either case. A 1 dBA increase in the highest load testing suggests
that the S12 PSU fan was ramping up a bit, but it was difficult to identify.

The measurements did not reflect what I heard, however. The P180 tended to
sound softer and smoother. Without the Nexus fan on the HS, the overall perceived
noise was quite low. By comparison, SLK3000B always sounded sharper and metallic.
Even when the measured SPL was the same, the P180 had a smoother, more subdued
sonic signature.

The subjective difference probably stems from the superior materials used
in the construction of the P180, resulting in a much lower level of noise
from vibration and resonance. The composite side panels may also have been
better at blocking the noise, as the lack of sharp, high frequency noise in
the P180 was quite striking.

The P180 seemed to react less than the SLK3000B to the vibration contributed by the fans and the single
hard drive. Seek noise in particular
was very muted in the P180 and easy to ignore. In contrast, the occasional
thrumming noise in the SLK3000B left no doubt about exactly when the Raptor
hard drive was being accessed.

There is no doubt in my mind that the P180 is much more pleasant to hear.
The audio recordings below should demonstrate this: Please pay attention to the quality
of the sound, not just the volume. These recordings are roughly the same
volume, but, in my opinion, the recording of the P180 is much less intrusive. (Editor’s Note: The fidelity of your audio playback system will impinge on your ability to resolve the differences.)

MP3:
P180 “Hot Potato” Configuration 4: 25 dBA/1m

MP3:
SLK3000B Configuration: 25 dBA/1m

The recording microphone was positioned ~15″ off the floor and 3″ from
the front panel.
This was the positioning for all the P180 and SLK3000B case recordings. The
cases were on a carpeted concrete floor.

CASE COMPARISON (continued)

Comparison Two

As configured, the SLK3000B was able to cope reasonably well with the high-end
system used in our testing. Because the power supply was the only thermally
controlled fan in both systems, the excellent behavior of the Seasonic S12-430 kept
the noise level fairly low, even with the system under full load.

For the second comparison, the power supply in each system was swapped for
an older model, a Seasonic Super Silencer 460 with the classic single
80mm fan design. The Super Silencer spent some time as an SPCR favorite, but
it is no longer in production and its noise performance under load is not
on par with the S12-430 used in the first comparison. However,
its acoustics (and fan behavior under load) is still quite good, and representative
of many current quiet power supplies.

Seasonic Super Silencer 460 in the SLK3000B.

ROUND 2: Antec P180 vs. SLK3000B, with Seasonic Super Silencer PSU
Load	System	HS Fan	CPU	GPU	AC Power	PSU fan RPM	SPL
Idle	P180	Fanless	28°C	67°C	112W	1440	26 dBA/1m
	SLK3000B	Fanless	29°C	61°C	112W	1440	27 dBA/1m
2 x CPUBurn	P180	Fanless	65°C	67°C	238W	1620	28 dBA/1m
	SLK3000B	Fanless	72°C*	62°C	238W	2420	38 dBA/1m
	P180	Nexus @ 12V	54°C	67°C	239W	1620	29 dBA/1m
	SLK3000B	Nexus @ 12V	53°C	62°C	239W	2420	39 dBA/1m
CPUBurn + Prime95 + 3DMark05	P180	Fanless	67°C	103°C**	294W (peak)	1700	29 dBA/1m
	SLK3000B	Fanless	73°C*	92°C**	294W (peak)	2900	44 dBA/1m
	P180	Nexus @ 12V	56°C	101°C**	295W (peak)	1700	30 dBA/1m
	SLK3000B	Nexus @ 12V	58°C	92°C**	295W (peak)	2900	44 dBA/1m
*CPU Throttling occurred in these configurations. ** VGA temperatures under 3DMark05 correspond to the peak level seen between separate 3DMark05 benchmarks, and were not easily repeatable. Temperatures are reported as estimates, and cannot be directly compared.

It is interesting to note that the total AC power draw of the system hardly
changed. At full system load, this Super Silencer sample has the about same efficiency
as the S12-430 sample used before. The fan behavior and noise are
a completely different story.

Unlike the S12-430, whose fan hardly ramped up at all during all the testing,
the Super Silencer 400 responded audibly to increased temperature under load.
This was the expected result of swapping the power supply, but it is worth
pointing out that the fan speed increased slightly even in the P180.

CPU Cooling

The CPU and VGA temperatures in the P180 should have been identical to the previous set
to tests. Swapping the power supply in the lower chamber should have no effect on temperatures
in the upper chamber. However, a 1~2°C drop in CPU temperature under load
and a 1~2°C rise in GPU temperature was observed with the different power
supply. The most likely reason for this variance is a slight difference in
the way the cables were routed.

The change in power supply had a greater effect on the CPU temperature in
the SLK3000B. Without the fan on the heatsink, the CPU became hot enough for
protective throttling (of CPU clock & voltage) to occur. This was a 6~7°C
increase, and it would have been greater had CPU throttling not kicked in.
It occurred in spite of the substantial increase in the PSU fan speed, from
1400 RPM at idle to 2400 at CPUBurn load and 2900 RPM at the maximum possible
load. Intuitively, the extra airflow should help CPU cooling, but perhaps
the interaction between the exhaust fan, the side “blowhole” over
the CPU, and the increased fan speed in the PSU reduced the total air speed
over the Ninja heatsink.

With the Nexus fan on the heatsink, CPU temperatures in the SLK3000B were
much better and remained on par with the P180, although they did vary slightly
from the results seen in the first test.

VGA Cooling

No significant changes in the GPU temperature occurred after the power supply
swap. The performance in the SLK3000B continued to be slightly better than
in the P180. The largest difference was observed in the P180 with the GPU
under load, but there was no rational reason for this temperature to change
so much, so the variance is most likely a indication of how unreliable the
GPU load measurements are.

Noise

After the swap to the Seasonic Super Silencer, the overall noise of both
system went up a bit at idle. The change was bigger with the SLK3000B, where
the rougher, sharper quality of the 80mm fan in the Super Silencer could be
distinguished. It was more muted in the P180.

With the CPU under load, however, the difference in noise between the two
systems went from “close” to “no comparison“.
While the SLK3000B topped out at 44 dBA/1m under the heaviest load, the P180
stayed at a modest 30 dBA/1m — not silent, but hardly noisy, especially
for a system of this power. In the SLK3000B, the power supply fan could often
be heard ramping up and down in response to changes in heat at its intake,
especially during the dynamic load of the 3DMark05 benchmark. This ramping
was much less marked in the P180, where the increase in noise was gradual.
(Note: There was no point in making recordings of the two cases; one
is LOUD, the other is quiet.)

The lower noise of the P180 system can be attributed to the different position
of the power supply. The separate power supply chamber ensures that the intake
temperature at the PSU remains constant regardless of the heat in the upper
chamber. The PSU only has to deal with its own internal heat, and therefore
its fan doesn’t need to spin as quickly or loudly. The choice of power supply
with the P180 is therefore much less crucial than with a more conventional
case.

Comparison Three

The three drives added to the P180 system during
the hard drive testing were installed in the SLK3000B along with the system
drive. The Raptor in the P180 and the Caviar SE in the SLK3000B are close
enough in their level of vibration that they can be counted as identical for
the purposes of this test. (This test was conducted with the S12-430 PSU in
the systems.)

ROUND 3: Antec P180 vs. Antec SLK3000B, w/ Four Hard Drives at Idle
System	System State	HDD Temp.	SPL
SLK3000B	Idle	38°C	28-31 dBA/1m
	2 x CPUBurn	38°C	29-33 dBA/1m
P180: PSU/HDD Setup 2 (no fan, exhaust vents sealed)	Idle	43°C	26 dBA/1m
	2 x CPUBurn	44°C	26-27 dBA/1m
P180: PSU/HDD Setup 4 (fan set to Low)	Idle	37°C	28 dBA/1m
	2 x CPUBurn	35°C	28 dBA/1m

The SPL measurements make clear the difference between the P180 and the SLK3000B:
The three extra hard drives add as much as 6 dBA/1m to the system noise in
the SLK3000B, while adding only 1-2 dBA/1m in the P180. The difference in
even more marked subjectively. The SLK3000B pulses with sound
as the resonances of the different hard drives interact with each other; the
result is a low frequency hum that rises and falls in volume over a period
of ten seconds. The variable nature of the sound makes it hard to ignore.
The P180 didn’t exhibit a trace of this sound; even with four drives installed,
no significant resonance could be heard.

MP3:
P180 “Hot Potato”, HDD/PSU Setup 2 (four hard drives installed):
26 dBA/1m

MP3:
P180 “Hot Potato”, HDD Setup 4 (four hard drives installed, PSU
chamberfan on Low): 28 dBA/1m

MP3:
SLK3000B with four hard drives installed: 28-31 dBA/1m

Comparison Four

As a final proof of the superiority of the drive mounting system
in the P180, the two systems were reverted to their original configurations,
and measurements were made with the WD Raptor hard drive under heavy use. A large
file copy was set up to ensure that the seek noise remained fairly constant
while measurement was taking place. The 10 dBA/1m difference between the two
systems is quite telling, but the most dramatic difference can be heard in
the MP3 recordings of the seek noise.

In the P180, seeks sound much as they do in free air: They are
short and sharp, although the composite panels of the P180 manage to take
some of the bite out of their attack. On the other hand, the SLK3000B does
nothing for the quality of the seek noise: The whole case is shaken with vibration
and resonance when the drive is put to work.

MP3:
P180 “Hot Potato”, WD Raptor Drive, idle/seek: 25/29 dBA/1m

MP3:
SLK3000B, WD Raptor Drive, idle/seek: 26/39
dBA/1m

ROUND 4: Antec P180 vs. Antec SLK3000B, Hard Drives Seek Noise
System	System State	SPL (Peak)
SLK3000B	Heavy HDD Seek	39 dBA/1m
P180	Heavy HDD Seek	29 dBA/1m

MID-RANGE SYSTEM

This is the midrange system mentioned many pages ago. Here are the components:

• AMD Athlon 64 3500+ (Winchester core)
• DFI LanParty UT nF4-D motherboard
• Corsair Memory TWINX1024-4000PRO – Matched 2 x 512mb DDRAM
• Arctic Cooling Silencer 64 Ultra TC heatsink/fan
• AOpen Aeolus 6600GT-DV128 PCIe video card
• Nexus 80 fan at 12V on Zalman fan bracket over VGA card
• Antec Phantom 350 fanless power supply
• 2 x Maxtor Diamondmax 10 300G drives in RAID 0, mounted in lower HDD cage
• Nexus 120 fan at 7V in PSU chamber
• Antec P180 case

A64-3500+ System in P180.

Close-up of Antec Phantom 350 PSU, Nexus 120 fan and Maxtor DiamondMax 10 drives
in RAID.

Zalman bracket over AOpen 6600GT VGA card in main chamber.

As you can imagine, it’s a pretty speedy system, not wanting for performance
in any way. The Windows XP installation was faster than usual, perhaps because
of the RAID drives — although it always seemed to me that the optical drive
would have been the bottleneck. Photoshop, MS Office, and various other apps
all worked very snappily, as did Windows XP in general.

Ambient temperature during testing was 22°C, and ambient noise level was
18 dBA/1m.

Configuration One

The starting configuration was as follows:

1. Cool’n’Quiet was enabled. AC power draw with CnQ on was 92W; with
   it off, it was 106W. There was no difference in acoustic noise between the
   two settings.
2. The noisy little Northbridge HSF on the DFI board was replaced with a
   fanless Zalman NB heatsink. This made the top PCIe video slot unusable,
   so the AOpen 6600 card was installed in the second, lower PCIe video slot.
3. The built-in fan on the VGA card was unplugged & a Nexus 80 fan at
   12V was mounted on a Zalman fan bracket over the VGA card. The P180 VGA
   duct was removed, based on findings from the experimentation described earlier.
4. The fan in the PSU chamberwas swapped for a Nexus 120 running at 7V.
5. The upper drive cage and front fan holder were removed entirely to
   minimize the airflow impedance near the intake.
6. Airflow in the upper chamber was provided by the the rear Antec TriCool
   fan, set on Low.
7. The top fan was removed and the top vent was covered with a thick
   piece of dense foam. It does not completely block airflow; some airflow can
   be felt from the outside.

This system proved to be very quiet in idle or at load. The only change in
noise came from the thermally-controlled fan on the Arctic Cooling Silencer
64 Ultra TC heatsink/fan, which went from ~1000 RPM at idle to ~1600 RPM at
the highest load. It was a minor, almost undetectable change. The CPU ran
amazingly cool considering this modest HSF. Unfortunately, the GPU was not
adequately cooled by the stock HS without its fan running, even with the 80mm
Nexus fan running at 12V over it. Jaggies and other screen artifacts began
appearing on the screen about half way through the demanding third combo-torture
test as shown in the table below.

This led to the second configuration, a quick and dirty solution to the VGA
cooling problem:

Configuration Two

Only one change was made from the first configuration above: The built-in fan on the VGA card was plugged into a Zalman Fanmate, and undervolted to 8.25V,
the level at which the fan noise dropped to the level of the other fans. The Nexus 80 fan (at 12V) above the VGA card remained in place. Only one test was run; it’s the only one that really matters.

The GPU temperature dropped dramatically, while the other parameters remained the same. There was no evidence of any GPU misbehavior on the screen. The price was a small increase in noise, reflected in the 26 dBA/1m SPL reading. In reality, it was a bit more audible that this number would indicate. That small fan on the VGA card has a distinct signature which came through even at the undervolted level. Still, the overall noise was quite modest.

MP3: P180 “Midrange System”, Configuration 1, Idle: 24 dBA/1m

In the end, I’d say that the sonic results of Configuration One can
be obtained with the much better GPU temperature of Configuration Two
if a capable aftermarket heatsink such as the Zalman
ZM80 or similar was installed on the video card.

CONCLUSIONS

The Antec P180 is designed for quiet computing, and based on this criterion
alone, it delivers handsomely. The separate PSU/HDD chamber works very well,
and ensures that most power supplies will not ramp up except with exceptionally
powerful systems under very high loads. This feature is unique, and allows a much wider variety of power supplies to be used for a quiet system. Any power supply that is quiet at idle but ramps up too quickly under load can probably remain very quiet in the P180.

Antec’s silicone grommets are soft enough to reduce HDD vibration greatly,
and the composite panel construction ensures that any remaining vibration is
unlikely to cause resonance. These features make hard drive suspension unnecessary
in the P180, making it much easier to build a quiet system and increasing the
range of hard drives that can be used. As you should have heard in one of the sound recordings above, even the loud seeks of the
WD Raptor stayed well-muted in the P180.

Last but not least, the dual fan configuration at the rear of the case provides CPU cooling at least as good as any conventional case for any system that locates the CPU socket near the top rear corner of the board — most of them. There probably aren’t many cases capable of cooling a 3.8 GHz Prescott processor passively, even with a heatsink as capable as the Scythe Ninja. The bulk of the testing in the P180 was done with just one of the provided 120mm TriCool fans on Low, with very good results.
One can imagine the level of cooling that is available if both fans are brought
into play at mid or high speed, although this configuration
would not be quiet.

The VGA duct does not provide
very good cooling to the VGA card. Even without the duct this area of the case
doesn’t seem to “breathe” as well as the SLK3000B. The VGA duct does not match the rest of the case: The
complexity of its installation is at odds with the smooth sliding
drive cages, and its tendency to resonate disrupts the copious attention paid
to noise-reduction everywhere else. I cannot think of any configuration
where I would not remove the duct entirely. Anyone planning to build a
quiet gaming rig should find — or mod — a VGA card that is quiet in
its own right. Any VGA card would probably
be best served by using a Zalman fan bracket with a quiet 80mm or 120mm fan
instead of the duct.

The other drawbacks of the P180 are easier to handle. The difficult cable
management that results from the unusual position of the power supply is well
compensated by the benefits of isolating the power supply from the rest of the
system and is a requirement of the design rather than an engineering oversight.
Likewise, the complexity of the installation is due to the dual-chamber layout
of the case.

The P180 is not a beginner’s case. In the right hands, it has the potential
to outdo almost any other case on the market in terms of noise and thermals,
but some knowledge of thermodynamics and acoustics is necessary to get the most
out of it. A beginner may be luckier with the P180 than another case because
the choice of hard drive and power supply are less crucial, but the cable installation
will take a fair bit of time.

To conclude: The P180 has more potential for silencing than any other case
I have ever encountered. Although some benefits, such as the damped panels,
can be appreciated by anybody, the true power of this case will be felt most
by the experienced user who knows how to take advantage of its many unique features.
About the only thing you might add to a quiet build in this case is a bit of acoustic damping foam to cut the last bit of sonic reflections inside the case. No doubt the hardcore silencers will still find ways to modify and improve this case,
but the average user will find that this case provides a quality of noise that
is unachievable in any other case without modification.

Many Thanks to:

Antec
Inc. for the P180, Phantom PSU and SLK3000B case samples
AMD for the Athlon 64 3500+
sample
AOpen
for the Aeolus 6600GT & 6800GT video cards and i915Ga-PLF motherboard samples
Corsair Memory for the matched 2 x 512mb TWINX1024-4000PRO DDRAM
DFI for the
DFI LanParty UT nF4-D motherboard sample
Intel for the 660 Processor sample

Maxtor for the Diamondmax 10 300G samples

Scythe for the Scythe Ninja CPU heatsink
Seasonic for the S12 and Super Silencer PSU samples
Western Digital for the Raptor hard drive sample
EndPCNoise for the Nexus 120 fans

* * *

You can support SPCR and get a cool black version of the P180
with a laser-cut aluminum SPCR badge exclusively from EndPCNoise
in the US and from

FrontierPC
in Canada. European resellers will also be appointed in the near future.

Discuss this article in the SPCR Forums.

POSTSCRIPT: V1.1

June 15, 2006 by Devon
Cooke

Time passes and products evolve. It’s been almost a year since the P180 was
first released to much fanfare along with SPCR’s longest review ever (in three
parts). Antec has finally released the black model of the P180 to the general
public (previously, it was an SPCR-exclusive product). At the same time, they
revised the original P180 to address several minor issues that arose after the
case was released:

• The VGA duct has been removed entirely.
• Vented PCI slot covers have been added to improve airflow around the VGA
  cards.
• New fan clips that allow a 120mm fan to be mounted directly in front of
  the VGA cards are included.
• The power supply channel is now cooled by a standard Tricool fan; the original
  38mm thick fan is gone.
• The silicone padding around the power supply frame has been improved.
• The front door is now made of the same 3-ply material that is used in the
  rest of the case, resolving warping issues with the door.

These changes are minor and do not warrant another full review. However, they
do affect my original conclusions about the case, especially where the VGA duct
is concerned, so it is worth giving them a quick look.

My biggest criticism about the original P180 was the fact that the VGA duct
was noisy, ineffective, and complicated installation. Using somewhat strong
language, I advised users to avoid this particular feature: “I cannot
think of any configuration where I would not remove the duct entirely.”
Apparently, Antec (and SPCR’s editor, Mike Chin, who helped design the case)
was listening. The VGA duct has been dropped entirely in favor of a much simpler
and, hopefully, more effective system.

Vented PCI slot covers significantly change the airflow around the VGA card(s).

Two new features have been introduced to replace the duct. The first is the
use of vented PCI slot covers to provide additional airflow in the immediate
vicinity of the expansion cards. This feature was recently used to great success
in Mike Chin’s second collaboration with Antec, the
NSK2400 desktop case.

The second feature is the inclusion of a pair of fan clips that allow an additional
fan to be installed between the top drive bay and the expansion slots, giving
the slots the direct airflow that the duct was supposed to provide with minimal
hassle. When the fan is installed, the expansion cards can now have a dedicated
cooling fan to provide a logical front-to-back airflow configuration through
the VGA cards. Given the natural dividing baffle effect of a typical high end video card into upper and lower areas (and the way two such vidcard in SLI/Crossfire mode form a channel), the close positioning of this extra fan is very welcome for those who use the P180 in a high end gaming rig.

Simple fan clips with illustrated mounting instructions.

The clips allow an additional fan to be installed that provides direct airflow beneath the top VGA card, with the heated air exhausting out the back panel expansion slot openings.

The power supply channel has also received a couple of minor updates. The first
is a simple fan swap. The original version of the case featured an extra-thick 120x38mm cooling fan that, unlike the rest of the fans in the case, had no business in a case designed for silence. It is now a 120x25mm fan like in the rest in the case. The change does a lot to lower the out-of-the-box noise.

The fan in the PSU channel has been replaced with a quieter version.

The second change to the PSU channel simply implements the silicone padding
around the PSU frame in a better way. The original mounting system attempted
to isolate the power supply by surrounding it with a thin silicone pad. However,
the pedestal on which the power supply rested had no such padding, effectively
short-circuiting the attempt at soft-mounting. This has now been corrected;
the power supply is now padded on all sides. The frame also fits more loosely
than before, allowing the silicone to do its part to absorb vibration.

The PSU frame now fits more loosely and the silicone padding has been expanded.

The final change has little to do with acoustics, but nevertheless fixes a
serious aesthetic complaint that many
users had. The problem was that the door was prone to warping if subjected
to rapid changes in temperature, leading to a variety of fit-and-finish issued,
including warping, separation of the door’s two layers, and a “bulge”
that would not allow the door to lie flush against the bezel.

Antec’s solution was simple: The door is now made from the same three-ply construction as the rest of the case, which means that the two outer sides expand and contract together with temperature changes. Early users of the new doors have reported that this has fixed the problem. On a side note, the original review sample of the P180 currently occupies the space
under my desk to the right of my knees, and has never shown any signs of warping.

The new, 3-ply door is no longer susceptible to the warping that affected the original 2-ply door. being a bit thicker, it may actually improve acoustic islolation slightly as well.

All in all, it is good to see that Antec has kept up their support of the P180. These changes are a sign that the P180 has outgrown its teething problems and that Antec probably intends to keep this model around for a while longer. The removal of the VGA duct and the replacement of the bottom fan address the only two major issues that I had with the original release. Now, a year
later, the P180 is worthier than ever of the praise that I gave it in the original
review: “The Antec P180 is designed for quiet computing, and based on
this criterion alone, it delivers handsomely.”