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Asus EN3650 Silent Graphics Card

Asus is extending the use of its passive V-Cool heatsink down to a video card with a price tag that appeals to the masses, based around an ATI Radeon 3650 GPU. We know it won’t be as fast as the 3800 series, but will it do high def video, idle at lower power, and stay cool in a low airflow system?

June 20, 2008 by Lawrence Lee

PCI-E Video Card
Street Price

Most PC graphical subsystems are not stressed heavily during the
course a typical day. They are usually tasked with menial duties
such as rendering the desktop, and displaying pictures and videos. During
these times, the power consumption of the system should be as low as possible.
The Radeon HD 3850 and 3870
of graphics cards, while being fairly powerful gaming cards,
impressed us greatly with their extremely low idle power consumption. The Geforce
on the other hand, seemed almost wasteful in comparison, using
10-15W more than ATI’s offerings during idle. Keep a system on for
8+ hours a day, and that can add up, creating a toll on the environment, and
the electricity bill.

Enter the EAH3650 Silent.

For those of us who don’t play games “seriously”, or do so at lower resolutions, a more
basic GPU is enough. The Asus EAH3650 Silent is such a card. While
it won’t play Call of Duty 4 at full-tilt, being part of the HD 3000 family,
it should deliver excellent power consumption and good high definition playback
capability. With a built-in audio processor for HDMI audio, it is also ideal for
a home theater PC system. Last but not least, it equipped with a 100% silent cooling

The retil box is wastefully big. Geforce 6800XT pictured for scaling.


Box contents.


Asus EAH3650 SILENT/HTDI/512M: Specifications
(from the
product web page
Graphics Engine ATI Radeon HD 3650
Bus Standard PCI Express 2.0
Video Memory DDR3 512MB
Engine Clock 725 MHz
Memory Clock 1.4 GHz ( 700 MHz DDR3 )
Memory Interface 128-bit
CRT Max Resolution 2048 x 1536
DVI Max Resolution 2560 x 1600
D-Sub Output Yes x 1 (via DVI to D-Sub adaptor x
1 )
DVI Output Yes x 2 (DVI-I)
HDMI Output Yes x 1 (via DVI to HDMI adaptor x
1 )
HDTV Output (YPbPr) Yes
HDCP Support Yes
TV Output Yes (Composite)
Adapter/Cable Bundled 1 x DVI to D-Sub adaptor
1 x DVI to HDMI adaptor
1 x HDTV-out cable
Software Bundled ASUS Utilities & Driver
ASUS Features V-Cool Heatsink


Though the HD3650 is meant to be a mid-range part, the heatsink employed looks
very impressive. It is similar to that used in the Asus EN9600GT Silent Edition
Graphics Card
which is part of the growing Asus family of fanless video cards.

The “V-Cool” heatsink is a completely passive, dual slot cooling
solution. The card itself is fairly short, and the heatsink actually overhangs
it by more than an inch length-wise. The design is very similar of the heatsink
found on the Asus EN9600GT Silent which utilized three heatpipes. The Geforce
9600GT is a much more powerful card designed with gaming in mind, thus the EAH3650
gets only a single heatpipe.


The cooler is separated into two sections. The black portion pictured above
left is composed of a metal alloy, shaped into thick, long fins. The second
section is a series of thin, tightly packed aluminum fins toward the back of
the card.


The EAH3650 supports dual DVI-I outputs as well as component out. The yellow
DVI port also carries audio and can be converted into an HDMI signal using the
supplied adapter. The ventilation grill at the back is stylized with Asus’ name.


Aside from aesthetics, the design has little technical merit. Extensive
variations in fin structure and orientation does not serve much purpose in a
low airflow environment. A graphics card’s placement in a typical ATX case is
subject only to incidental airflow unless there happens to be a side fan.


The cooler is held on with only four screws and is easily removable. With
the heatsink being so long, the center can act like a fulcrum — if force
is applied, the cooler can be tipped on either side.


The GPU core is the sole beneficiary of the V-Cool heatsink. All other components
on the PCB, including the memory chips, are untouched by the heatsink..


The heatsink was taken off after testing so that the breaking
of the thermal bond between the stock thermal compound, the base, and the GPU
would not affect the test results. The heatsink detached easily revealing the PCB and exposed GPU
core and some residue from the thick thermal compound used to facilitate heat


The black portion of the cooler is completely solid at the center
with only three slits for ventilation. The fins at the rear of the card are
soldered to a single heatpipe emanating from the copper base.


The more massive black section of the heatsink makes contact
with about two thirds of the base, though as one giant block of metal, it
is unlikely to be an effective design for dissapating heat. On the EN9600GT
Silent, two extra heatpipes left very little room for contact between these
two pieces.


Installed in our video card test platform.


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.

The anatomy of our test platform is detailed here: Updated
VGA Card/Cooler Test Platform

Testing Procedures

Our first test involves recording the system power consumption using a Seasonic
Power Angel as well as 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 video 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 system.

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
happen to 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.


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.


1920×1080 | 24fps | ~19mbps
WVC1: Drag Race is a recording of a scene from
a network television re-encoded with TMPGEnc with the WVC1 codec. It
features a high-paced drag race. It is the most demanding clip in our
test suite.

Estimating DC Power

The following power efficiency figures were obtained for the Seasonic
used in our test system:
Seasonic S12-500 / 600
DC Output (W)
AC Input (W)


This data is enough to give us a very good estimate of DC power 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
DC (Est.)
Ambient temperature: 21°C

Asus EAH3650 Silent:

VGA Test Bed: Asus EAH3650 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.

The passive heatsink employed by Asus passed our thermal testing with flying colors.
No artifacts or other instability was exhibited by the system during stress
testing and the temperatures were excellent. With the case fan at 7V, there
is very little airflow in our test system, yet the GPU temperature was a
very impressive 74°C under load. The previous two passively cooled cards
we tested, the Asus EN8600GT and EN9600GT Silent both exceeded 90°C under
the same conditions.

Our testbed setup has the system fan is in close proximity
to the CPU, resulting in much lower CPU temperatures when the system fan speed
is increased. At the same time, the GPU temperature also improved significantly.
Despite its distance from the graphics card, the rear exhaust fan’s speed
had a dramatic effect on the GPU cooler’s effectiveness. The system fan is
one of our reference Nexus 120mm fans and it is fairly quiet and not powerful
by any stretch of the imagination — this illustrates that no matter how little or distant,
system airflow is paramount for passive cooling components in a PC.



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 3650 vs. HD 3850
vs. 9600GT
GPU State
Asus EAH3650
Sapphire HD3850
Asus EN9600GT
DC (Est.)
DC (Est.)
DC (Est.)

The HD 3650 series is a low end part compared to the HD 3850, yet its idle
power consumption was a fair bit higher. This could stem from the fact that
a passively cooled card runs hotter and thus is less efficient than if
it was actively cooled, but the Sapphire HD 3850 we tested had a fan that would
refuse to spin up, and its core temperature was unusually high during load testing.
The EAH3650 is still more efficient than nVidia’s 9600GT though.

When stressed the card only consumed an extra 37W, which is very good for
a modern graphics card. Its modest power demand is probably the top reason
the passive heatsink works so well.

Video Playback

Video Playback Results: EAH3650
Video Clip
Mean CPU Usage
Peak CPU Usage
AC Power
Rush Hour (H.264)
Coral Reef (WMV3)
Flight Sim. (WVC1)
Drag Race (WVC1)

The EAH3650 passed our playback tests flawlessly. It utilizes
the same Universal Video Decoder unit as the rest of the ATI HD 3000 series
so this was no surprise.

Video Playback Comparison: HD 3650 vs. HD 3850
Video Clip
Asus EAH3650
Sapphire HD 3850
Mean CPU
Peak CPU
AC Power
Mean CPU
Peak CPU
AC Power
Rush Hour
Coral Reef
Flight Sim.

In terms of CPU usage, compared to the HD 3850, the results were fairly even,
as expected. Power consumption on the other hand, was consistently higher throughout.
A thought occured to us during video testing: audio may be responsible for this
continuing anomaly. The EAH3650 has a built in HD audio processor for its HDMI
audio functionality. A typical PCI sound card can add up to 5W to a system’s
power consumption.

HDMI Output

We connected the card with the supplied adapter via HDMI to a BenQ FP94VW
monitor. The video portion of the signal worked perfectly. The proper resolution
was available in the Display Settings and the screen looked crisp and clear.
The ATI HD Audio device was detected in the Device Manager and the driver for
it installed without incident. Despite this, we were unable to get any sound
via the monitor’s headphone output. It’s somewhat ironic that the card’s audio
functionality may have been utilizing extra resources yet did not give us any


For a sense of how
well the HD 3650 performs in games, check out the reviews at X-bit
, Legit
and Digital
. The
general consensus is that the HD 3650 is a entry level graphics card with performance
close to, but not quite matching the Geforce 8600GT and Radeon HD2600XT. It
is not a good choice for the most recent 3D games except at lower resolutions with little or
no extra image quality options enabled. The EAH3650 Silent may be slightly worse
as the memory speed is 100Mhz slower than the reference specifications.

Video Playback: Video playback was good, as the HD 3650 uses the same
UVD chip as the products higher up in ATI’s product line.

HDMI: The video signal worked fine, but the audio did not work on our standard video test system. Apparently, the problem is not isolated to just our sample. A member of the SPCR forum wrote: “The EAH3650 is confirmed in many places to have broken HDMI audio. Only Catalyst 8.2 works, and my understanding is that no newer drivers will ever work.”

Cooling: The stock cooler did an excellent job — the card’s GPU was
cooled more than adequately without generating any noise. Even with very limited
airflow, the V-Cool heatsink was more than up to the task. The temperatures seen here were far lower than with the nVidia 9600GT GPU on the Asus EN9600GT graphics card, which uses a variant of the same heatsink.

Power Consumption: For whatever reason (possibly the audio functionality),
the EAH3650 Silent seemed to consume more power than it’s big brother, the HD
3850, when idle and during video playback. It may be that there was simply something
wrong with our sample. Despite this, it is still a more efficient choice than
nVidia’s offerings.

The Asus EAH3650 Silent is an excellent choice for a silent PC. Its passive
heatsink did an exceptional job cooling the GPU, even in
our arduous test system with very limited airflow. We wish all entry level graphics
cards would come with fanless coolers — it really isn’t that hard to keep
them cool. The EAH3650 Silent doesn’t have the horsepower for “serious” gaming — an odd juxtaposition of terms —
but it can do in a pinch at lower resolutions, and with older games. It is not for anyone wanting to use the card with HDMI for a home theater PC. However, this does not stop you from getting audio out to the TV or monitor… albeit, in a less convenient way.


* Good high definition video playback
* Excellent, fanless heatsink
* Low load power consumption


* Lacklustre gaming performance
* Higher idle & 2D power consumption than HD 3850
* Could not get HDMI audio working

Our thanks to ASUSTeK
for the video card sample.

* * *

Articles of Related Interest
Asus EN9600GT Silent Edition
Graphics Card

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

* * *

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