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Arctic Cooling Accelero S2 VGA Cooler + Turbo Module

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A slightly smaller, slightly cheaper version of the AC Accelero S1 performs a bit worse. Is there really a market for this inexpensive, admittedly brilliant performing VGA cooler when the slightly bigger S1 (Rev 2) fits the same video cards, and performs better for only $3 more?

Jan 16, 2008 by Lawrence
Lee

Products
Arctic Cooling Accelero S2
VGA Cooler
Arctic Cooling Turbo Module
Dual 80x15mm fans
Manufacturer
Arctic
Cooling
Market Price
US$20 & $8

The recently reviewed Arctic
Cooling Accelero S1
left us with a very positive impression — finally
there is a dual-slot, passive heatsink that could handle the majority of
modern video cards with ease. Its little brother, the Accelero S2, is a slightly
smaller version with only two heatpipes. It is designed with less demanding
GPUs in mind. Along with the S2, we’ll be taking a look at Arctic Cooling’s
Turbo Module, an add-on for the S1/S2 comprised of two frameless 80mm fans.

Judging from our S1 testing, any amount of direct airflow blowing between
the fins will improve performance dramatically. If this holds true, the Turbo
Module should do fairly well complimenting the S2’s cooling performance, so
then ultimately, the amount of noise it produces will determine whether or
not it gets our final recommendation.

ACCELERO S2 OVERVIEW


The Accelero S2 box.

Accelero S2: Main Features (from the
product web page
)
Features & Brief
Our Comment
Noiseless Cooling
Passively cooled
of course, it will be completely silent.
Dual Heat Pipes
Half that of the
S1.
Memory Cooling
8 ramsinks included.
Hopefully the adhesive will hold this time around.
High Reliability Difficult to verify.
Low Weight 30% lighter than
the S1.
6 Years Warranty Six is such an odd number — must be a European thing.
Accelero S2: Technical Data (from the
product web page
)
Heatsink Dimensions 140(L) x 188(W) x 32(H)
mm
Heat Pipe Dimensions 6 mm x 2
Weight 202 grams
Accessories 8 Memory Heat Sinks
Compatibility ATI: HD 2400 series, X1650,
X1600, X1550, X1300, X1050 series, X850, X800, X700, X600, X550, X300
series, 9XXX series

nVIDIA: GeForce 8500, 8400 series, GeForce 7600, 7300, 6600 series,
FX 5950, 5900, 5700 (Ultra) series, FX 5600, 5500, 5200 series, GeForce
4 Ti, MX series

TURBO MODULE OVERVIEW


The Turbo Module box.

Turbo Module: Main Features (from the
product web page
)
Features & Brief
Our Comment
Dual High Performance Fans
One larger fan would have been more
efficient.
Enhance Cooling Performance Not a hard claim to make. The S1
did not need very much airflow to achieve stellar performance.
Extremely Quiet
We shall see.
High Reliability
Difficult to verify.
Easy Installation
No screws or tools requried.
Low Weight
Mostly because the fans do not have
frames.
Long Lifetime Difficult to verify.
6 Years Warranty Seems like overkill in the case of
the Turbo Module. It’s probably not worth sending back to the manufacturer.
Turbo Module: Technical Data (from the
product web page
)
Fan: 80 x 80 x 15 mm (each)
Fan Speed: 1500 RPM
Air Flow: 42 CFM
Bearing: Sleeve Bearing
Plug: 3 pin plug (with power plug
convertor)
Weight: 35 g (each)
Warranty: 6 Years

ACCELERO S2 DETAILS

The Accelero S2 uses the same basic design as the S1. The number of heatpipes
has been reduced from four to two and the length (or width as Arctic Cooling
refers to it, that is the dimension parallel to the expansion slots) has
been truncated from 215mm to 188mm – a difference of approximately one inch.
The weight is also significantly lower: 202g vs. the S1’s 290g. The overall
size is still immense when compared to other video card coolers.


The underside of the S2.

Instead of four mounting arms, a large metal plate forms a hood over the
base with multiple mounting points, making the S2 compatible with many graphics
cards. The base itself is virtually identical to that of the S1. The mounting
plate is a bit different, raised above the PCB, in line with the base. Rubber
spacers are required to bridge the gap. To keep these spacers on, a thin
layer of adhesive film surrounds the mounting holes on each side. This is
a bit of a lazy move on Arctic Cooling’s part. A year from now, the adhesive
may be dried up.


The S2 base.


The spacers glued on.

ACCELERO S2 INSTALLATION

Our standard test VGA card, the Radeon X1950XTX, was not compatible with
the S2, nor was our previous test card, the Geforce 6800XT. The Asus
EN8600GT Silent
edition from a previous review had to be used instead.
The Geforce 8600 series is not listed as compatible, but this particular
card has two sets of mounting holes with the smaller, interior set being
a perfect match. While these are present on many 8600 cards, its not universal,
which would explain why they are left off the compatibility list.


The backside of the Asus EN8600GT Silent edition.


The Asus EN8600GT stripped of its stock heatsink.

The ramsinks that came with our sample Arctic Cooling S1 simply did not
stick, but the adhesive on the ramsinks supplied with the S2 was stronger, and all eight of the ramsinks stayed on. Perhaps newer shipments
have improved adhesive, or the un-sticky SI ramsinks were just the luck
of the draw. They are very simple aluminum heatsinks with a thick base and
five long fins. For passive cooling, you really don’t need anything fancy
in terms of design except for wide fin spacing. The VRM heatsinks from the
S1 package are absent as the S2 is not compatible with the X1800/X1900 series.


Screws and washers partially installed.

Aside from the rubber spacers, the installation procedure is identical
to the S1. Thermal compound was applied to the GPU core, the card was flipped
upside down onto the heatsink and ‘L’ clips were placed between the card
and heatsink. The ‘T’ clips that go on the top side of the heatsink were
omitted as they would interfere with the Turbo Module to be installed later.
Four washers and screws secured the S2 in place.


Installation completed.


A view of the base.


Capacitor clearance.


The S2 has a slight curve.

Note that the S2 has a gentle but undeniable curve, which may cause interference
with large expansion cards directly below it. This could be Arctic Cooling’s
way of sneaking in an extra bit of heat dissipation area.


TURBO MODULE DETAILS & INSTALLATION

The Turbo Module is a set of two, 15mm thick, 80mm wide fans wired in parallel to the
same 3-pin cable. A 3-pin to 4-pin adapter is included for those wishing
to power it directly off the power supply. No fan controller is supplied,
so they are expected to run at 12V. The fans are frameless — this
decreases turbulence, a major source of fan noise. However, the
airflow produced is not as directed. The bearings are of the sleeve variety
— a somewhat questionable choice considering that typical sleeve bearings
do not hold up well in a horizontal orientation. (Please see Anatomy
of the Silent Fan
for more information about fan bearings.)


Turbo Module: Right-side up and Upside-down.


The Turbo Module, latched on tight.

The Turbo Module basically clip on to the fins of the S1 or S2 heatsinks.
The bottom of each fan has three pairs of legs which are inserted straight
through the gaps in the heatsink. One pair runs parallel to the fins with
small hooks at the ends, grasping onto the outer edges of the fins like
a gynamst hanging off of the rings. Another two pairs run perpendicular,
with one meant to straddle a heatpipe while the other seems to have no purpose
other than to provide balance and/or symmetry.


Turbo Module installed. The fan cable should be tucked into one of
the fins to avoid impeding the fan blades.


From the side.


One leg is on shaky ground.

The Turbo Module was not a perfect fit on the S2. The fan on the left near
PCI slot covers was snug, but the fan on the right was lopsided. The problem
is the S2 (as well as S1) is not level in height all the way through. The
fins rise (or lower depending on which way you look at it) slightly near
the edge of the board presumably to avoid larger components. The leg hooks
on the fan are the same length, however, so one of them on the second fan
was loose.


The tension from the Turbo Module’s legs can cause fins to bend slightly.
Note how much beyond the VGA card’s perimeter the S2 extends.


TEST METHODOLOGY

Our test procedure is an in-system test, designed to determine whether the
cooler is adequate for use in a low-noise system. By adequately cooled,
we mean cooled well enough that no misbehavior related to thermal overload is
exhibited. Thermal misbehavior in a graphics card can show up in a variety of
ways, including:

  • Sudden system shutdown or reboot without warning.
  • Jaggies and other visual artifacts on the screen.
  • Motion slowing and/or screen freezing.

Any of these misbehaviors are annoying at best and dangerous at worst —
dangerous to the health and lifespan of the graphics card, and sometimes to
the system OS.

Test Platform

Measurement and Analysis Tools

  • ATI Tool
    version 0.26

    as a tool for stressing the GPU
  • CPUBurn
    P6
    processor stress software.
  • SpeedFan
    version 4.33
    to show CPU & GPU temperature
  • Seasonic
    Power Angel
    AC power meter, used to monitor the power consumption
    of the system
  • A custom-built internal variable fan speed controller to power the
    system fan
  • A custom-built external variable fan speed controller to power the
    VGA heatsink fan (if applicable)
  • Bruel & Kjaer (B&K) model 2203 Sound Level Meter, used to
    accurately measure SPL (sound pressure level) down to 20 dBA and below.

  • The exterior view of our test platform.

The Antec P180 case has two front intakes — the bottom one feeds
fresh air to the hard drive and power supply section while the top one allows
airflow into the rest of the system. The stock filter and door over the intake
vent for the main chamber are removed — replaced with the metal mesh from
the top panel 120mm fan. The filter for the lower PSU/HDD chamber is retained,
but its cover door is also removed to reduce airflow impedance. The front door
is cast away as well to improve airflow. The top three optical drive bays are
covered with a block of open-cell foam which allows some air to flow in but
also absorbs much of the internal sound from coming out.


The internals of our new testbed.

The processor is cooled by a modified Gigabyte G-Power 2 Pro without its plastic
shroud utilizing a Scythe Slip Stream 120mm 500RPM fan, connected directly to
the motherboard’s CPU fan header — it is completely inaudible. Above it,
a block of foam is positioned on the ceiling over top fan vent, which also draws
some air in when the system is running.

The only system fan is a Nexus 120mm mounted in the rear exhaust position with
silicon rubber nubs made expressly to reduce vibration conduction into the case.
It is powered by the PSU through to a customized fan speed controller using
zener diodes. A knob protruding from the wall of foam at the front allows the
fan voltage to be easily varied.

The power supply is a Seasonic S12-600 with the stock fan replaced by a Scythe
Slip Stream 120mm 800RPM fan, hard-wired to run at 5V. The fan just barely starts
up, and spins extremely slowly, at ~400RPM. Air expelled from the PSU is only
mildly warm, even during long sessions of high power testing.

The notebook hard drive is suspended in the lower drive bay with zip ties and
cloth elastic with a 2mm round cross-section. No vibration from the drive can
be felt on the drive bay. Foam is attached to both sides of the compartment
divider as an extra silencing measure.

The overall noise level of the system is excellent at only 19 dBA@1m with
the system fan @ 7V. For comparison, during the quietest moments in our lab
with all the computers turned off, the ambient noise level is around 17 dBA.

Our main test consists of ATI Tool’s artifact scanner running in conjunction
with CPUBurn to stress both the graphics card and processor simultaneously.
It is a realistic test that mimics the stress on the CPU and GPU produced by
a modern video game, only more consistantly. The software is left running until
the GPU temperature stabilizes for at least 10 minutes at which point, both
the CPU and GPU temperatures are recorded. In addition we also take measurements
of the system’s overall noise level (from 1m away) and power consumption using
a B&K Sound Meter and a Seasonic Power Angel respectively. If the heatsink
has a fan, the procedure is repeated at various fan speeds while the system
fan is left at the lowest setting of 7V. If it is a passive cooler, the system
fan instead is varied to study the effect of system airflow on the heatsink’s
performance. If artifacts are detected in ATI Tool or other instability is noted,
the heatsink is deemed inadequate to cool the video card in our test system.
Preliminary testing is also done at idle, and with only CPUBurn running for
comparison.

Ambient conditions during testing were 22°C and 18 dBA.


TEST RESULTS

First the EN8600GT Silent was tested with the stock cooler. It’s a simple heatsink
comprised of a copper base connected to a single heatpipe, and thick aluminum
fins.


The Asus EN8600GT Silent with stock heatsink.


The underside, cleaned up.

Asus EN8600GT with Stock Heatsink
State
System Fan Speed
System Noise
GPU Temp.
CPU Temp.
System Power
Idle
7V

19 dBA

55°C
22°C
94W
CPUBurn
56°C
39°C
163W
CPUBurn + ATI Tool
98°C
42°C
185W
9V
21 dBA
93°C
37°C
184W
12V
23 dBA
86°C
183W

With the system fan at 7V, the GPU temperature with the stock heatsink was a sizzling 98°C, which
also seemed to affect the CPU temperature. Turning up the system fan speed resulted
in significant improvements.


The S2 installed in our test platform.

Asus EN8600GT with AC Accelero S2 (Passive)
State
System Fan Speed
System Noise
GPU Temp.
CPU Temp.
Idle
7V

19 dBA

44°C
22°C
CPUBurn
45°C
39°C
CPUBurn + ATI Tool
63°C
40°C
9V
21 dBA
60°C
37°C
12V
23 dBA
57°C
35°C

The Accelero S2, with 30°C to 35°C improvements across the board, makes
the stock heatsink look foolish. The results were also better than the EN8600GT
OC Gear
card which we tested on our old test platform. That card used
a Zalman-type cooling solution, with which we recorded a load temperature of
70°C @ 22 dBA. Even after accounting for the temperature difference between
our old test platform and our new one (about 5°C), the S2 is still slightly
better. Any time a passive heatsink can match or beat the performance of an
active cooler, it’s a great achievment.

TEST RESULTS CONTINUED

The Turbo Module was added to the S2 heatsink for further testing.


Accelero S2 and Turbo Module installed in our test platform.

Results: Accelero S2 + Turbo Module
State
Fan Speed
System Noise
GPU Temp.
CPU Temp.
Idle
5V

19 dBA

39°C
22°C
CPUBurn
40°C
38°C
CPUBurn + ATI Tool
52°C
7V
49°C
39°C
9V
20 dBA
48°C
12V
22 dBA
46°C
System fan @ 7V

@5V and @7V: Inaudible in our lab. Ticking could be heard from within
one foot, but other than that, the noise was below ambient. At 5V, the GPU temperature
was a chilly 49°C. Increasing it to 7V effected a marginal improvement.

@9V: In the open, the fans were audible but not unpleasant. Close
up, the ticking was slightly less noticeable as the sound of airflow drowned
it out. However, it was inaudible from more than two feet away. Inside the
test system, the fans’ presence was barely detectable. The temperature difference
was just measurable.

@12V: The noise signature was very smooth. At close range the ticking
became a slight buzzing but most of it was overtaken by the sound of rushing
air. Inside the case, it was audible, but very benign. A two degree improvement
over 9V was not enough to justify the extra noise, especially in a silent
PC.

Comparison: Stock vs. S2 (Passive) vs. S2 + Turbo
Module

Stock

Accelero S2
Passive
Accelero S2 +
Turbo Module
SPL@1m
GPU Temp.
SPL@1m
GPU Temp.
SPL@1m
GPU Temp.
19 dBA
98°C
19 dBA
63°C
19 dBA
49°C
21dBA
93°C
21dBA
60°C
20 dBA
48°C
23 dBA
86°C
23 dBA
57°C
22 dBA
46°C

Adding the Turbo Module to the S2 decreased the GPU temperature by more than
10°C at comparable noise levels. As a bonus the fan was inaudible at 7V.
Increasing the fan speed seems unnecessary. These results seem to corroborate
our findings with the S1 — that only a small amount of direct airflow is
required to get the best performance / noise ratio from the Accelero coolers. Arctic Cooling is apparently aware of this, or they would’ve
made these fans spin much faster.

FINAL THOUGHTS

The Accelero S2 is a highly proficient cooler. It put the stock passive cooler
of the Asus EN8600GT Silent edition to shame, besting it by about 30°C.
It also matched the fan-cooled stock cooler of the EN8600GT
OC Gear
, which is very impressive.

A question that arises is whether the S2 is ideal for its intended application,
which is the tier of VGA cards one step down from the hottest. These VGA cards are
often used in smaller and slimmer cases, expecially HTPC cases. The S2 is shorter
than the S1, but the length is not a problem, because it’s no longer than any
VGA card. The width is the same as the S1, however, and that means it’s incompatible
with slimmer cases. (Of course, for a creative hardware modder, it’s no big
challenge to reduce the size of the S2 with minimal effect on cooling.)


It’s this dimension that makes the S2 less than ideal for smaller cases.

With the very recent introduction of the Accelero S1 Rev. 2, which expands the S1’s compatibility
to all the cards that the S2 fits, the S2 seems almost redundant. It’s hardly smaller, only a few dollars cheaper, and doesn’t perform quite as well. Most consumers would just buy the S1 rev. 2. A smaller heatsink that doesn’t extend so far beyond the boundaries of
the typical midrange VGA card actually has a bigger potential market than the
S2.

The Turbo Module is quiet, effective, and only occupies the space of one extra
expansion slot. If space is limited, it’s a good choice over strapping your
own fan to the S1/S2. Quiet, 15mm depth fans are basically unheard of. The Turbo
Module would serve the S1 better than the S2, as there aren’t really any cards
on the S2’s compatibility list that need the extra airflow. The sleeve bearings
may not last as long in the vertical orientation the fans will be run in (with
any tower case), but perhaps the fans are light enough for this not to be a
serious issue. The fan mounting system also isn’t ideal — it’s a good concept,
but the execution doesn’t quite fit the fin design of the Accelero line.

Arctic Cooling Accelero S2
Pros * Great passive performance
* Even better performance with direct airflow
* Easy to install
* Only takes up one extra slot
* Incredibly affordable
Cons * Not small enough for narrower cases
* Compatibility limited to less demanding cards
Arctic Cooling Turbo Module
Pros * Surprisingly quiet
* Increases performance
* Easy to install
* Only takes up one extra slot
* Inexpensive
Cons * Uses sleeve bearing fans
* Mounting scheme could be better

Thanks to Arctic
Cooling
***

SPCR Articles of Related Interest:

Arctic Cooling
Accelero S1 VGA Cooler

Updated
VGA Card/Cooler Test Platform

Zalman VF1000 LED Graphics
Card Cooler

VGA Cooler Roundup: A
Thermalright, two Zalmans, and an Arctic Cooling

* * *

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