ASUS GeForce GTX 680 DirectCU II OC

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

3D Performance Benchmarks (for low-end/budget graphics processors only)

Estimating DC Power

The following power efficiency figures were obtained for the Kingwin LZP-1000 used in our test system:

Kingwin LZP-1000 Test Results
DC Output (W)
65.5
90.7
149.0
199.6
251.2
300.3
400.9
AC Input (W)
81
105
166
211
265
322
426
Efficiency
80.8%
86.4%
89.8%
92.8%
92.9%
93.5%
94.1%

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.

Ambient Noise Level

Our test system's CPU fan is a low speed Scythe that is set to full speed at all times. The two Antec TrueQuiet 120 case fans are connected to the motherboard and are controlled using SpeedFan. Three standard speed settings have been established for testing.

VGA Test System:
Anechoic chamber measurements
Setting
System SPL@1m
System Fan Speed
High (loud)
26 dBA
1130 RPM
Med (quiet)
18 dBA
820 RPM
Low (silent)
12~13 dBA
580 RPM

When testing video cards and coolers with active cooling, the low setting will be used. For passive cards and heatsinks, all three settings will be tested to determine the effect of system airflow on cooling performance.

Video Test Suite


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


1080p | 24fps | ~22 mbps

H.264/MKV: A custom 1080p H.264 encoded clip inside an Matroska container.



720p | 24fps | ~1.2 mbps

Flash 720p: The Dark Knight Rises Official Trailer #3, a 720p YouTube HD trailer.



1080p | 24fps | ~2.3 mbps

Flash 1080p: The Dark Knight Rises Official Trailer #3, the same YouTube HD trailer in 1080p.


Testing Procedures

Our first test involves monitoring the system power consumption as well as CPU and GPU temperatures during different states, idle, under load with Prime95 to stress the processor, and Prime95 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 we deem the card's fan control to be overly aggressive, we can adjust them at our discretion.

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.

Lastly, for low-end and budget graphics cards, we also run a few gaming benchmarks to get a general idea of the GPU's 3D performance. We don't feel this is necessary for high-end models as there are many websites that do this in painstaking detail.



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