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TEST METHODOLOGY
Our test procedure is an in-system test, designed to:
1. 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, reboot without warning, or loss of display signal
- 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.
Test Platform
Measurement and Analysis Tools
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 GPU-Z during
different states: Idle, under load with CPUBurn running to stress the processor,
and ATI and FurMark running to stress both the CPU and GPU simultaneously. This
last state is an extremely stressful, worst case scenario test which generates
more heat and higher power consumption than can be produced by a modern video
game. If it can survive this torture in our low airflow system, it should be
able to function nominally in the majority of PCs.
The software is left running until the GPU temperature remains stable for at
least 10 minutes. If artifacts are detected by ATI's artifact scanner or by
eye or any 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 (if applicable) while the system case 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. System
noise measurements are made at each fan speed.
Our second test procedure is to run the system through a video test suite featuring
a variety of high definition clips. During playback, a CPU usage graph is created
by the Windows Task Manger for analysis to determine the average CPU usage.
High CPU usage is indicative of poor video decoding ability. If the video (and/or
audio) skips or freezes, we conclude the GPU (in conjunction with the processor)
is inadequate to decompress the clip properly. Power consumption during playback
of high definition video is also recorded.
H.264/VC-1 Test Clips
H.264 and VC-1 are codecs commonly used in high definition movie videos on
the web (like Quicktime movie trailers and the like) and also in Blu-ray discs.
To play these clips, we use Cyberlink PowerDVD.
1080p | 24fps | ~10mbps |
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1080p | 24fps | ~8mbps |
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x264/MKV Video Test Clips
MKV (Matroska) is a very popular online multimedia container
used for high definition content, usually using x264 (a free, open source
H.264 encoder) for video. The clips were taken from two longer videos
— the most demanding one minute portions were used. To play them
we use Media Player Classic Home Cinema, configured in the most suitable
manner depending on the GPU. For Intel/ATI graphics the player is configured
to use DXVA (DirectX Video Acceleration) and for Nvidia graphics we use
CoreAVC to enable CUDA (Compute Unified Device Architecture) support.
720p | 24fps | ~11mbps |
x264 720p: Undead Battle is a 720p x264 clip encoded
from the Blu-ray version of a major motion picture. It features
a battle with undead warriors.
|
1080p | 24fps | ~14mbps |
x264 1080p: Spaceship is a 1080p x264 clip encoded from
the Blu-ray version of an animated short film. It features a hapless
robot trying to repair a lamp on a spaceship.
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Estimating DC Power
The following power efficiency figures were obtained for the
Seasonic S12-600
used in our test system:
|
Seasonic S12-500 / 600 TEST RESULTS
|
|
DC Output (W)
|
65.3
|
89.7
|
148.7
|
198.5
|
249.5
|
300.2
|
|
AC Input (W)
|
87.0
|
115.0
|
183.1
|
242.1
|
305.0
|
370.2
|
|
Efficiency
|
75.1%
|
78.0%
|
81.2%
|
82.0%
|
81.8%
|
81.1%
|
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.
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