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Asus EN9600GT Silent Edition Graphics Card

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Asus has a large, growing stable of fanlessly cooled graphics cards. Their latest sports a sports car engine design theme on a GF 9600GT GPU platform. We take it out for a test drive.

Asus EN9600GT Silent Edition Graphics Card

April 14, 2008 by Lawrence

Asus EN9600GT Silent/HTDI/512M
PCI-E Video Card
Suggested Retail

Video cards are one of the toughest components to cool in a PC. Its location
within the ATX form factor case, the limited amount of space around it, and
the lack of tertiary cooling makes heat dissipation challenging. To complicate
matters, graphics processing units have become extremely complex, and many have
more raw computing power than CPUs. nVidia’s latest, the Geforce 9800 series,
has more than a billion transistors. But over the past year or so, efficiency
has been improving at an even faster rate. Power draw often now decreases with
a new generation GPU — ATI’s
HD 3800 series
graphics cards are a good example. With lower power demands,
cooling is becoming easier and lower speed fans can be employed. Long gone are
the days when you would have to put up with a blow dryer in their system to
get the best in gaming performance — some now deaf users remember the the
Geforce FX 5800 well.

Asus has not been shy to experiment with video card coolers; they are one of
the few companies who routinely push the reference cooler aside. Currently,
they seem to have developed a fondness for radial coolers such as the one found
on the EN8600GT OC Gear.
They also offer a large variety of passively cooled cards. Asus’ latest card,
the EN9600GT Silent edition, is their most powerful, fanless graphics card to
date. With the same clock speeds as the reference Geforce 9600GT, there’s no
compromise in exchange for the absence of noise. The 9600GT GPU supports DirectX
10, Shader Model 4.0, and the PCI-Express 2.0 standard, and touts twice as many
stream processors and increased clock speeds across the board compared to its
predecessor, the 8600GTS.

The EN9600GT Silent comes in a ridiculously ginormous box.

More than half of the packaging is for accessories, none of which require
the extra space. The box could easily have been half the size. We hope
Asus isn’t overcompensating for something.

Asus EN9600GT Silent: Specifications (from the
product press release
Model Model EN9600GT SILENT/HTDI/512M
Graphics Engine GeForce 9600GT
Video Memory 512M DDR3
Engine Clock 650 MHz
Shader Clock 1625MHz
Memory Clock 1.8GHz (900MHz DDR3)
Memory Interface 256 bit
DVI Max. Resolution 2560 * 1600
Bus Standard PCI Express 2.0
DVI Output DVI-I * 2
HDCP compliant YES
HDMI Output YES, via DVI to HDMI adaptor**
D-Sub Output YES, via DVI to D-Sub adaptor
HDTV Output YES, via HDTV Out cable
TV Output YES, via S-Video to Composite
Adaptor/Cable Bundled DVI-to-D-Sub adaptor
HDTV-out cable
Power Cable
DVI-to-HDMI adaptor
S/PDIF cable
Software Bundled ASUS Utilities & Driver
Notes **To enable HDMI audio out
function, a motherboard with internal S/PDIF header and the correct connection
of S/PDIF cable with graphics card and motherboard are needed.
• System Fan in chassis is recommended
for using the SILENT graphics card
• For the best heat dissipating results, please place the PC in a location
with good ventilation
• Specifications, PCB color and bundled software versions are subject
to change without notice
• Brand and product names mentioned are trademarks of their respective


The EN9600GT Silent’s passive cooler utilizes three aluminum alloy heatpipes,
each attached to a separate section of densely-pressed fins. In between,
and surrounding them are several metallic pieces joined together in an
unusual pattern and painted black.

The black metal forms long, thick fins parallel to the length of the card,
with sets of "ribs" on both sides. At the center where the Asus
nameplate resides, the fins run perpendicular. At the back of the card
it forms a shroud. Also note: The protruding loop of heatpipe is problematic for lower-profile HTPC cases such as the Antec Fusion; it make the card too tall to physically fit in the case.

The fins at the very rear of the card are aligned in a zipper formation,
designed to trap and guide any air entering through the intake vent. The
card comes with dual dual-link DVI (the yellow one is HDMI-capable) and
S-Video/Component-out ports.

Underneath the heatsink, there is no extra cooling for memory chips or
any of the voltage regulation circuitry. The circuit board is quite bare.

During installation, two of long black fins interfered with the PCI-E
power connector. The clip would not lock on without wedging itself under
the heatsink. We resolved this by twisting the offending clip completely

Though it is not visible in any of the pictures, the screws toward the
vent side of the cooler did not appear to be engaged all the way. We tightened
them as best we could before testing and hoped for the best.


Like many modern nVidia cards, there are four spring-loaded screws on
the back holding the cooler in place. The PCB is roughly 21.9cm in length.
The center heatpipe visible above juts out past the edge of the card
by approximately 2cm.

The base of the heatsink is very typical modern GPU heatpipe coolers.
The heatpipes are soldered to a very thin copper base.

The black half of the heatsink is solid on the underside, so air cannot
pass through it vertically. Two of the heatpipes are flattened and soldered
to the underside of the fins.

Before passing judgment on such an unusual design, we wanted
to know exactly what their motivation and inspiration came from. The official
press release had several interesting passages detailed below.

V-Cool Heatsink Description (from the
product press release
Quote Our Comment
"The V-Cool Heatsink’s
super racing car engine design stands as a testament to the unique and
high-precision craftsmanship from ASUS; and combines a stylish outlook
with powerful cooling performance"
Creating a heatsink
that looks like a race car engine is nothing short of an engineering marvel.
However, while it certainly looks interesting, we have to scoff at it
being described as "stylish."
"Phasing in the V-Engine
concept* (*A V-Engine means that the pistons are aligned so that they
appear to be in a ‘V’ when viewed along the axis of the crankshaft.
The V configuration reduces the overall engine length and weight compared
to an equivalent straight engine.), the ideally arranged V-fins dissipate
heat evenly with a minimum of space required"
We have to give them
points purely for committing so strongly to the engine analogy, but none
of it seems to have any relevance to heatsinks.
"…while the high-density
zipper array fin module utilizes the Intercooler technology** (** Intercooler
Technology means that air flows over the outside of the intercooler’s
fins, which in turn cool the air inside the intercooler) to maximize the
surface area exposed to the air to help heat dissipation.
By making the fins
at the back form a "zipper array" air passes not just over the
fins, but through them. They’re assuming there’s enough airflow inside
to keep it from just lingering.

Overall, we were more confused after reading the press release
than before. As far as we can tell the black portion makes little direct
contact with any of the heatpipes or the copper base. We have many unanswered

  • Why does the V-Engline even exist?
  • Why use two separate sets of material?
  • Why are the fins not all the same thickness?
  • And most importantly, why are all the fins pointing
    in different directions?!

With such a convoluted form, it seems to us that the V-Engine’s
only function is to keep the entire assembly from falling apart and to look
"stylish." Never mind; the proof will be in the cooling.


Our test procedure is an in-system test, designed to:

1. Determine whether the card’s 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.

2. Estimate the card’s power consumption. This is a good indicator of how
efficient the card is and will have an effect on how hot the stock cooler
becomes due to power lost in the form of heat. The lower the better.

3. Determine the card’s ability to play back high definition video, to see
if whether it is a suitable choice for a home theater PC.

Test Platform

Measurement and Analysis Tools

  • ATITool
    version 0.26

    as a tool for stressing the GPU and to show GPU temperature
  • CPUBurn
    to stress the CPU
  • SpeedFan
    version 4.33
    to show CPU temperature
  • Cyberlink
    PowerDVD 7.3
    to play video.
  • Seasonic
    Power Angel
    AC power meter, used to measure the power consumption
    of the system
  • A custom-built variable fan speed controller to power the system
  • Bruel & Kjaer (B&K) model 2203 Sound Level Meter. Used to
    accurately measure SPL (sound pressure level) down to 20 dBA and below.

Our test platform is detailed here: Updated
VGA Card/Cooler Test Platform

Testing Procedures

Our first test involves monitoring the system power consumption (using a Seasonic
Power Angel), and CPU and GPU temperatures (using SpeedFan and ATITool or just
SpeedFan if a nVidia based card is used) during different states:

  • Idle,
  • with CPUBurn running to stress the processor, and
  • with CPUBurn and ATITool’s artifact scanner running to stress both the CPU
    and GPU simultaneously.

This last state mimics the stress on the CPU and GPU produced by a modern computer
game. The software is left running until the GPU temperature stabilizes for
at least 10 minutes. If artifacts are detected in ATITool or other instability
is noted, the heatsink is deemed inadequate to cool the video card in our test

If the heatsink has a fan, the load state tests are repeated at various fan
speeds while the system fan is left at its lowest setting of 7V. If the card
utilizes a passive cooler, the system fan is varied instead to study the effect
of system airflow on the heatsink’s performance. A B&K Sound Meter is employed
to take system noise measurements at each fan speed.

Video Playback Testing

For our second test, we play a variety of video clips with PowerDVD. A CPU
usage graph is created via the Windows Task Manger for analysis to determine
the approximate mean and peak CPU usage. If the card (in conjunction with the
processor) is unable to properly decompress the clip, the video will skip or
freeze, often with instances of extremely high CPU usage as the system struggles
to play it back. High CPU usage is undesirable as it increases power consumption,
and leaves fewer resources for background tasks and other applications that
might be running during playback. Power draw is also recorded during playback.

Video Test Suite

1920×816 | 24fps | ~10mbps
Rush Hour 3 Trailer 1
is encoded with H.264. It has a good mixture
of light and dark scenes, interspersed with fast-motion action and cutaways.

1920×1080 | 24fps | ~20mbps
MPEG-2: Blu-ray Trailers is a collection of trailers
taken from the Terminator 2: Judgment Day Blu-ray disc. It was ripped
with AnyDVD for playback via hard disk drive. It’s a full 1080p clip encoded
with MPEG-2.

1440×1080 | 24fps | ~8mbps
Coral Reef Adventure trailer
is encoded in VC-1 using the
WMV3 codec (commonly recognized by the moniker, "HD WMV").
It features multiple outdoor landscape and dark underwater scenes.

1280×720 | 60fps | ~12mbps
WVC1: Microsoft Flight Simulator X trailer is
encoded in VC-1. It’s a compilation of in-game action from a third person
point of view. It is encoded using the Windows Media Video 9 Advanced
Profile (aka WVC1) codec — a much more demanding implementation
of VC-1.

Estimating DC Power

The Seasonic
used in our test system was tested and measured to have the
following the power efficiency:

Seasonic S12-500 / 600
DC Output (W)
AC Input (W)

This data is enough to give us a very good estimate of DC demand in our test system. We extrapolate the DC power output from the measured AC power input based on this data. We won’t go through the math; it’s easy enough to figure out for yourself if you really want to.


Baseline, with Integrated Graphics: First, here are the results of
our baseline results of the system with just its integrated graphics, without
a discrete video card. We’ll also need the power consumption reading during
CPUBurn to estimate the actual power draw of discrete card later.

VGA Test Bed: Baseline Results
(no discrete graphics card installed)
System State
CPU Temp
System Power
Ambient temperature: 21°C

Asus EN9600GT Silent:

VGA Test Bed: Asus EN9600GT SILENT/HTDI/512M
System State
Sys. Fan Speed
Noise Level
System Power
DC (Est.)
20 dBA
CPUBurn + ATITool
CPUBurn + ATITool
21 dBA
CPUBurn + ATITool
23 dBA
Ambient temperature: 21°C, ambient noise level:
18 dBA @1m.

Despite our misgivings about its design, the passive heatsink employed by
Asus passed testing with flying colors. No visible artifacts or other instability
was exhibited during stress testing, and the temperatures were adequate. With
the system fan at its minimum speed, the GPU temperature reached 91°C
— while certainly not a good result, it is acceptable in the context
of an artificially extended, extreme load on both GPU and CPU. The heat emanating
off the card affected the CPU temperature, which was 10°C higher than
in the baseline system. Increasing speed of the the system fan, which is in
close proximity to the CPU heatsink, remedied the situation.

With a little extra airflow, the GPU ran much cooler. Its temperature dropped
by 10°C with the case fan at 9V, and a further 7°C with the case fan
at 12V. This is consistent with our previous testing with passive video card
heatsinks — airflow, no matter how indirect, is vital. Our test system
has no intake fan, and the exhaust fan is a Nexus 120mm, which does not push
much air. The 74°C GPU and 38°C CPU temperatures reached with this
case fan set at 12V is very good.

It should also be noted that high GPU temperature led to high power consumption.
When CPUBurn and ATITool were run with the system fan at 7V, the power draw
read 208W initially. The power gradually increased as the card heated up,
eventually reaching a plateau of 220W. This is increased occurred because
the power efficiency of voltage regulators (and other components) on the board
decreased as they became hotter. That’s extra incentive to keep your graphics
card cool.



The power consumption of an add-on video card can be estimated by comparing
the total system power draw with and without the card installed on our test system. Our results
were derived thus:

1. Power consumption of the graphics card at idle – When CPUBurn is run on a system, the video card is not stressed at all, and stays in idle mode. This is true whether the video card is integrated or an add-on PCIe 16X device. Hence, when the system power under CPUBurn with just the integrated graphics is subtracted from the system power under CPUBurn with the add-on card, we obtain the increase in idle power of the add-on card. (The actual idle power of the add-on card cannot be derived, because the integrated graphics does draw some power — we’d guess no more than a watt or two.)

2. Power consumption of the graphics card under load – The power draw of the system is measured with the add-on video card, with CPUBurn and ATITool running simultaneously. Then the power of the baseline system (with integrated graphics) running just CPUBurn is subtracted. The difference is the load power of the add-on card. (If you want to nitpick, the 1~2W power of the integrated graphics at idle should be added to this number.) Any load on
the CPU from ATITool should not skew the results, since the CPU was running at
full load in both systems.

Power Consumption Comparison: HD 3850 vs. HD 3870
vs. 9600GT
GPU State
HD 3850
HD 3870
DC (Est.)
DC (Est.)
DC (Est.)

The Geforce 9600GT did not come even close to the Radeon HD3850 or 3870 in
idle power. When the card is sitting around doing nothing but rendering a
2D desktop, there’s a fair bit of wattage being wasted.

At load, the power demand of the 9600GT was right smack in the middle between
the two ATI cards.

(*Since our results for the baseline system were arrived at with the system
fan at 7V, we used the higher power consumption reading to estimate the 9600GT’s
power draw of 65W. With the system fan at 12V, when the card had better cooling,
the power draw was only 59W.

Video Playback

The EN9600GT Silent’s video playback capability was excellent. It clearly
had lower CPU usage during playback compared to the HD 3850/3870. Due to the
HD 3850’s exceptionally low power consumption, however, overall system power
consumption was still lower than with the 9600GT. The more power hungry HD
3870 also edged the 9600GT for lower system power during video playback.

Video Playback Comparison: HD 3850 vs. HD 3870
Video Clip
HD 3850
HD 3870
Mean CPU
Peak CPU
AC Power
Mean CPU
Peak CPU
AC Power
Mean CPU
Peak CPU
AC Power
No Data
No Data

HDMI Output

The HDMI output did not function properly with out test system. The HDMI
signal that was sent to our BenQ FP94VW was zoomed in and scaled incorrectly,
even though the driver was set to the proper resolution of 1440×900. To enable
HDMI audio, an S/PDIF cable must be connected from the graphics card to an
internal S/PDIF header on the motherboard; this is a feature that’s lacking
in our test platform motherboard, so we were not able to test HDMI audio.


Gaming Performance: This is a realm well covered by many other web sites,
so there’s little point for us to duplicate their efforts. We recommend the
9600GT reviews at TweakTown,
, and AnandTech.
The general consensus is that the 9600GT is a good value, midrange graphics
card, more or less comparable to the HD 3870, though it isn’t quite as adept
at rendering games at higher resolutions. Less demanding games such as Unreal
Tournament 3 or Call of Duty 4 can be played comfortably with most settings
at maximum.

Video Playback: nVidia’s PureVideo HD made video playback purely a formality.
It rendered all our tests clips easily and with less CPU assistance than ATI’s
Radeon HD 3850 or 3870.

Cooling: While we feel Asus could have done better, the passive heatsink managed to cool the card adequately, even in our
very low airflow test system. If you can put up with a little extra noise, a
little extra airflow is recommended, especially during extended high loads.

Power Consumption: On load, the power consumption of the 9600GT is right
where it should be, higher than the HD 3850, but lower than the HD 3870. When
idle or during low-load such as high-definition video playback however, it was
woefully inefficient compared to its ATI-based competitors.

The Asus EN9600GT Silent offers solid performance, both in gaming and in video
playback, and generates no noise. Most retail 9600GTs are selling for between
$150 and $180 USD at the time of writing; the slight premium for the Silent
edition may be worthwhile if minimal noise is important to you. If you are a
neophyte to PC modifications and don’t want to risk voiding the warranty, few
cards equipped with passive coolers are up to the Asus EN9600GT Silent’s caliber.
For more hands-on users, a cheaper 9600GT card and a DIY installation of an
Arctic Cooling Accelero S1
VGA heatsink is an obvious alternative.


* Good 3D Performance
* Excellent high definition playback
* Low load power consumption
* Fanless and silent


* Odd cooler design
* High idle power consumption
* HDMI video output needs improvement

Our thanks to ASUSTeK
for the video card sample.

* * *

Articles of Related Interest
ATI HD3850 & HD3870: Improved
Acoustics & Power Efficiency

Arctic Cooling Accelero S2 VGA
Cooler + Turbo Module

Arctic Cooling Accelero S1 VGA

Updated VGA Card/Cooler Test

Asus EN8600GT Silent/HTDP/512M
Graphics Card

* * *

this article in the SPCR forums

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