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Fanless PCIe Graphics Cards from Asus and Aopen

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A review of two more fanless video cards: The Asus Radeon EAX1600XT Silent/TVD/256M and the low profile AOpen Aeolus PCX6600-DV128LP. Both employ heatpipes to expand the cooling surface area onto the trace side of the video card for improved cooling. Are they suitable for dedicated silencers who want more than budget vidcard performance?

April 19, 2006 by Devon

AOpen Aeolus PCX6600-DV128LP
Fanless GeForce 6600 for PCIe
ASUS EAX1600XT Silent/TVD/256M
Fanless Radeon X1600XT for PCIe
Computer Inc.
Market Price
US$140 US$190

Finding a good fanless graphics card can be a bit of a challenge. There are lots
of them around, but the majority are entry-level cards. Then there’s the ever-present question of reliability.
It’s one thing to slap a fanless heatsink on a powerful card; it’s another thing
for that heatsink to perform well enough to cool it under stressful conditions in a real computer. Fanless cards must rely
on system airflow to move heat away from them, and it’s no simple trick to design
a passive heatsink that works well under a wide range of airflow conditions.

The Gigabyte GV-N66256DP was the first fanless graphics card we tested. It’s an AGP model. Two PCIe models are examined in this review: A low profile GeForce 6600 from AOpen, and a more recent Radeon X1600XT
from Asus:

The low profile AOpen Aeolus PCX6600-DV128LP card is targeted primarily at the home theater and SFF markets. Designing a video
card that is low profile and fanless is quite a challenge; the AOpen
needs to dissipate the same amount of heat with about half of the surface area
available to a more conventional card.

The ASUS EAX1600XT Silent/TVD/256M is a full size card with a mid/low performance GPU. However,
unlike the AOpen card, only the GPU is cooled; the RAM chips are open to the
air. If this cards shows any symptoms of overheating, it will be the RAM that
we suspect, not the GPU.


Aside from its low profile design, the Aeolus distinguishes itself from NVidia’s
reference 6600 by the speed and type of RAM that it uses: GDDR3 clocked 150
MHz faster than the DDR RAM used in NVidia’s version.

Half-height video cards are unusual.

The cooling system wedges the card between two chunky blocks of aluminum that
are connected around the back of the card by a pair of thin heatpipes. All of
the major chips, including the GPU and all the RAM chips, are covered by the
heatsinks. As can be expected of a passively cooled card, the heatsinks take
up quite a bit of space. Most of the additional volume is on the back side of
the card, making the Aeolus a double-width card. Given the layout of most SFF
systems, this may mean that the second expansion slot will be unusable, or,
even worse, the card may not fit at all. Tall capacitors or heatsinks around
the PCI Express slot may also cause problems.

Chunky aluminum heatsinks on both sides of the card.

A pair of heatpipes connect the two heatsinks.

Because of the low profile backplate, there is not enough room to fit the three
output connectors supported by the GeForce 6600 on the back panel. Only the
DVI-I and the TV-out port made it on to the back; the D-Sub VGA connector is
must be installed in a separate slot. A 15-pin ribbon cable is used to connect
the physical port to the card itself. Most people should be able to do without
this extra connector; single monitor setups can always use the DVI-I to VGA
adapter to hook up the appropriate type of monitor.

The VGA plug is included on a separate backplate…

…but a full size backplate will fit all three connectors…

…or it can be removed entirely if not needed.

SPECIFICATIONS: AOpen Aeolus PCX6600-DV256LP (from
web site
GPU nVIDIA GeForce 6600
Core Clock : 300MHz
DirectX Generation : 9
Video Memory -2ns
128 MB
Bus Type PCI-E
Highest Resolution /
Colors / Refresh Rate
2048 x 1536 / 32bit / 85Hz
RAMDAC Speed 400 MHz
Connectors DVI connector x 1
TV-Out (Composite&S-Video) x 1
VGA Out (15 Pin D-Sub) x 1
Form Factor Low Profile
Driver Support Direct3D, DirectDraw, DirectVideo and
ActiveX for Windows 2000/XP
OS: Windows 95/98/Me/2000/XP/NT4.0 and Linux
DirectX: 8 / 9
Software Package Auto driver installation wizard
User-friendly interface to control VGA settings
Accessories DVI-CRT converter x 1
User’s Guide : AOpen User’s Guide x 1
VGA driver disc : AOpen VGA driver disc x 1


ATI’s X1600XT series has been largely ignored by the gaming market
thanks to its sub-par performance in its price bracket. Its saving grace
is that it supports video in as well as video out, meaning that it
can operate as a TV capture card. Like AOpen’s low profile card, it will probably find
its biggest market in the HTPC market, where 3D performance is not that important,
and the additional cost over a low budget card can be justified by not needing
to buy a TV capture card. From this perspective, Asus’ decision to use a passive
cooler makes good sense, since the home theater market is more sensitive to

Full video in and out is supported for Composite and S-Video signals.

Unlike the AOpen card, Asus’ cooler only uses a single heatsink on the rear
side of the card. Two heatpipes transfer the heat to the heatsink around the
back of the card. The heatpipes are considerably thicker than those used by
AOpen. As mentioned, there are no heatsinks for the RAM chips or the Rage Theater
chip that enables the video capture capabilities of the card.

No heatsink fins here. Just a cooling block with two heatpipes coming out.

The heatsink does not make contact with the PCB, but hangs about half a centimeter
above it, allowing air to flow freely underneath it. The fins are individual
pieces of aluminum press-fitted on to the heatpipes. The heatsink is quite light, yet does not sacrifice cooling surface area. In fact, the surface area of the Asus heatsink is probably greater than both of the AOpen heatsinks combined.

The heatsink is also elevated above the base of the card to keep incompatibilities to a minimum. It is quite tall though, so it may cause issues with large CPU coolers if the CPU socket is located too close to the expansion slots.

The rear heatsink.

Heatpipes wrap around the tail end of the card…

…and spread out so that one heatpipe runs down each side of the heatsink.

SPECIFICATIONS: Asus EAX1600XT Silent/TVD/256M (from
web site
Graphics Engine ATI Radeon X1600XT
Video Memory 256 MB DDR3
Engine Clock 590 MHz
Memory Clock 1.38 GHz (690 MHz DDR3)
Bus Standard 16 Lanes PCI Express
Memory Interface 128 bit
Max Resolution 2048×1536
TV Output Yes
Video Input Yes
VGA Output Standard 15-pin D-Sub
DVI Output DVI-I
2nd VGA Output Yes, via DVI-to-VGA Adaptor
Adaptor/Cable Bundled 9-pin VIVO dongle
DVI-to-2nd VGA adaptor
3D Game Bundle Gamepack2 & Xpand Rally


This sturdy modified LX-6A19 (D8000) case from Cool Cases became our test system housing.

Our test procedure is an in-system test, designed to determine whether the
card is capable of being adequately cooled in a low-noise system. By adequately
, we mean cooled well enough so 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.

The test system was built around the coolest Intel Prescott-based processor
currently available. It’s a reasonable example of a mid-powered system that is fairly easy to keep
quiet. Almost all AMD-based processors should run cooler than our Pentium 520,
and almost all Intel-based desktop processors run hotter.

Test Platform

  • Intel
    processor (P4-2.8 Prescott, 1Mb cache, 800 MHz FSB in 775 casing).
    The combined power draw for the processor and the VRMs on the test motherboard
    was measured at 85.3 watts. Intel’s official TDP is 84 watts.
  • AOpen
    motherboard – Intel i945Ga Chipset; built-in VGA.
  • CoolerMaster Hyper 48
    heatsink, cooled by a Nexus 92mm fan undervolted to 7V.
  • Corsair DDR2 RAM, 1024 MB
  • Seagate Momentus 5400.2
    120 GB, 2-platter drive, suspended in a NoVibes III just inside the front intake vent.
  • Antec Neo HE 430
    ATX12V 2.01 compliant power supply, with a custom-built fresh air duct to
    ensure that the internal fan did not ramp up during testing.
  • Modified case from Cool Cases, outlined in detail below.
  • Nexus 120mm fan controlled by a variable voltage fan controller.

Measurement and Analysis Tools

System airflow is quite good, allowing the CPU and system fans to run at close
to inaudible speeds without compromising system cooling. The intake is about
the size of a 120mm fan. The only restriction is an air filter. A much more
restrictive cover for the filter was removed because it impeded the airflow
too much.

The one and only intake…

…and the same view, with the bezel removed.

There is only one point of exhaust: The 120mm case fan, which will be run at
a number of different speeds. The 80mm fan in the Neo HE power supply was taken
out of the picture by using a custom-built duct to ensure that the fan never
ramped up. The amount of airflow through the system can be controlled by adjusting
the speed of the case fan, thereby giving us a way of controlling how difficult
the thermal environment inside the case is.

A fresh air duct isolates the power supply from the rest of the system.

Only one possible points of exhaust: The orange case fan.
The fan in the power supply draws its air from a duct that does not interact
with the rest of the system airflow.

The airflow in our test rig is typical of an ATX case. Air flows in through
the intake near the bottom of the front panel, and is pulled up to the top rear
corner. Most of this air will bypass the expansion cards altogether, but a small
amount will be pulled across the rear of the card as it is pulled towards the
CPU heatsink and the case fan. All of the air will exit the case via the exhaust

The air will flow from the lower right to the upper left, drawing a small
amount of air across the VGA card.

Thermal testing consisted of running CPUBurn and the artifact scanner
built into ATI Tool simultaneously to generate as much heat as possible.
An initial test was run with the system fan running at 12 volts, and then the
fan was progressively slowed down to make the thermal environment more difficult.

Because no thermal monitoring was available on either of the two cards we tested,
CPU temperature was used to determine when the temperature had stabilized. Once
the temperature was determined to be stable, the stress software was left running
for at least another 20 minutes while we watched the screen carefully for visual
artifacts that might indicate overheating. The last test, with the system fan
running at 5 volts, was left running for more than an hour.

The cards were determined to have passed our testing if they managed to survive
the full two hour test without ATI Tool detecting any artifacts. RTHDRIBL was
also used to confirm visually that there were not artifacts present.


Ambient conditions at the time of testing were 22°C, and 120V / 60 Hz.

An initial testing phase was carried out using the integrated graphics on the
system motherboard to establish baseline levels for system power and CPU temperature.
Unfortunately, neither RTHDRIBL nor ATI Tool would not run on the integrated
graphics chip, so 3DMark05 was used in conjunction with CPUBurn to establish
the baseline power level. 3DMark05 produces a very dynamic load which is not
as strenuous as the constant load from ATI Tool, so the peak power was used
as a reference. Proper stress on the integrated graphics might raise the results
by another watt or two, but the impact on the rest of the system temperatures
would probably be minimal.

VGA Test Bed: Baseline Results (no external VGA card
System State
System Fan Voltage
System Power Consumption (AC)
CPU Temperature

Once the initial testing was complete, the real testing began.

AOpen Aeolus PCX6600-DV128LP

There’s not very much to say about AOpen’s card, because it failed about 20
minutes into the first session of RTHDRIBL. Before the failure, the system power
consumption gradually crept up by about 10W to a peak power consumption of 204W
just before it failed. Then, just as we were about to turn the fan down to the
next level, the screen went blank and we heard the BIOS beep as the computer
restarted. The acrid smell of burned electronics filled the room, and the card
no longer output any signal.

VGA Test Bed: AOpen Aeolus PCX6600-DV128LP
System State
System Fan Voltage
System Power Consumption (AC)
CPU Temperature
CPUBurn Only

We took the card apart to look for obvious signs of failure, but there were no visibly damaged components. Nevertheless, we never managed to get the
card working again on several other systems we tried.

A rough idea of the power consumption of the card can be judged by comparing
the total system power consumption with and without the card installed. The
following procedure was used to derive the estimates in the table below:

  1. The system AC power consumption was measured at various loads, with and without the video card.
  2. We used efficiency test results from our Antec Neo HE 430 review to estimate the approximate DC output power being delivered at the various AC input power measured.
  3. The power consumption of the graphics card at idle was assumed to be the difference in power demand between the two systems when both were running CPUBurn.
  4. The power consumption of the graphics card under load was assumed to be the difference between the system with the card running CPUBurn and RTHDRIBL simultaneously, and the baseline system running CPUBurn only. This ensured that any load on the CPU from RTHDRIBL did not skew the results, since the CPU was running at full load in both cases.
Video Card Power Consumption: AOpen Aeolus PCX6600-DV128LP
GPU State
Estimated DC Power Consumption
Total increase in System Power (AC)
Just before failure

Asus EAX1600XT Silent/TVD/256M

The Asus card completed our full
test without missing a beat. The system was left burning for more than two hours,
and ATI Tool never detected an artifact during that time. Our visual inspection
of the RTHDRIBL window confirmed the software test; we did not notice any visual

VGA Test Bed: Asus EAX1600XT Silent/TVD/256M
System State
System Fan Voltage
System Power Consumption (AC)
CPU Temperature
CPUBurn Only
CPUBurn & ATI Tool
CPUBurn & ATI Tool
CPUBurn & ATI Tool

While the card was under load, the heat that it gave off had the effect of
raising the CPU temperature by 4~5°C, pushing it dangerously close to overheating.
However, no CPU throttling was ever detected, so we concluded that no increase
in noise would have been needed to keep the CPU cool. Obviously, this result
will not be the same in every system, but it is worth noting that the additional
heat from the card can affect the rest of the system as well. In a system where
the CPU is already being cooled near its thermal limit, it is quite possible
that the system would need to be noisier to exhaust the heat from the passive

Video Card Power Consumption: Asus EAX1600XT Silent/TVD/256M
GPU State
Estimated DC Power Consumption
Total increase in System Power (AC)
ATI Tool

The EAX1600XT is hardly a cool-running card. With an estimated maximum power
of 46W, it may require more power than the CPU in some systems. That it could
be cooled with a neat, smallish passive heatsink makes the engineering quite impressive.


The failure of the AOpen card
does not speak highly of its suitability in a quiet system with slow fans and low airflow. Its low
profile just doesn’t provide enough space for a heatsink that can
cool it adequately. On the other hand, its form factor is one of its biggest
selling points; Low profile cards are not easy to find. With this in mind, it
is probably most accurate to say that the PCX6600-DV128LP is best suited to
specialized applications such as well-cooled home theater systems that do not
tax the 3D capabilities of the card.

The Asus card is a successful fanless graphics card. It survived our
toughest tests while putting out more heat than the Aopen card. The 4~5°C rise in CPU temperature
suggests that additional system cooling for some systems, depending on use patterns and ambient conditions. Certainly, an exhaust fan in the usual position above or beside the motherboard I/O panel is strongly recommended; it should be considered mandatory with this video card. Performance is perfectly good for any home theater PC application (especially with the breakout box for composite and S-video) and will likely be good enough for casual or less demanding gamers. It’s a good product with a clever, effective cooling system.

Many thanks to AOpen
for the samples of the PCX6600-DV128LP and the motherboard in the testbed,
to ASUSTeK for the
sample of the EAX1600XT Silent/TVD/256M.


SPCR Articles of Related Interest:
Gigabyte GV-N66256DP Fanless AGP video card
Chaintech AA6800GT + Arctic Cooling NV Silencer 5
Arctic Cooling ATI Silencer 2 VGA Cooler
Arctic Cooling VGA Silencer

Zalman ZM-80 VGA Heatpipe Cooler

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