Sapphire HD 7750 Ultimate Edition

Graphics Cards
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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 it affects how hot the GPU runs. The lower the better.

3. Determine how well the card decodes high definition video.

Test Platform


GPU-Z screenshot.

Measurement and Analysis Tools

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
400
AC Input (W)
87.0
115.0
183.1
242.1
305.0
370.2
500
Efficiency
75.1%
78.0%
81.2%
82.0%
81.8%
81.1%
80%

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.

Video Test Suite


1080p | 24fps | ~10Mbps
H.264: Rush Hour 3 Trailer 1 is a H.264 encoded clip inside an Apple Quicktime container.


1080p | 24fps | ~14Mbps

H.264: Space 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.



720p | 25fps | ~2Mbps

Flash: Iron Man Trailer #1 is the first trailer from the feature film of the same name. It's a YouTube HD video, though technically it is not quite 720p.

Testing Procedures

Our first test involves monitoring the system power consumption as well as CPU and GPU temperatures using SpeedFan and GPU-Z during different states:

  • Idle,
  • Under load with CPUBurn to stress the processor, and
  • CPUBurn plus FurMark 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 the card can survive this torture in our low airflow system, it should be able to function normally in the vast majority of PCs.

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.

Our second test procedure is to run the system through a video test suite featuring a variety of high definition clips played with PowerDVD and Mozilla Firefox (for Flash video). 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.

Finally we run a few gaming benchmarks to get a general idea of the GPU's 3D performance.



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