Testing (continued):
The data in the chart below was compiled while the systems were playing the Blu-Ray version of The Dark Knight on my HDTV at a resolution of 1080p. Despite the numbers, the Zotac motherboard failed this test because although it only used 37 percent of the CPU's resources, VC-1 video play back suffered and was what I would consider extremely jerky at 1080p. CPU load for the other three configurations was surprising, all three averaged near 12 percent total CPU overhead. Actual CPU loads ranged from 5 percent to 15 percent on all three ASUS boards, but generally hovered in the 12 percent range. System power consumption numbers were in line with what was expected, with the P5K-Premium's discrete GPU turning in the highest consumption and the underclocked P5N7A-VM consuming the least amount of power.
Nvidia's PureVideo HD decoding does a very good job of offloading video decoding tasks from the processor. This is evident in the CPU load results during Blu-Ray playback of the VC-1 content. I used Cyberlink's Power DVD 8.0 for the playback tests, but results were similar with Total Media Theater.
In this test I used the multi-threaded version of Prime95 and small FFT's to load the processors. Measurements were taken after running Prime95 for at least one hour. These temperatures are consistent with a bench system using a stock Intel cooler. Power consumption results were as expected, with the exception that both P5N7A-VM configurations turned in lower numbers (lower is better) than the ITX board.
