ATI Radeon HD 4870 X2 - AMD Back On Top
SD and HD Video Performance
We also did some testing of the Radeon HD 4870 X2's UVD video processing engine, in terms of both image quality and CPU utilization with some HQV and H.264 playback tests.
HQV is comprised of a sampling of SD video clips and test patterns that have been specifically designed to evaluate a variety of interlaced video signal processing tasks, including decoding, de-interlacing, motion correction, noise reduction, film cadence detection, and detail enhancement. As each clip is played, the viewer is required to "score" the image based on a predetermined set of criteria. The numbers listed below are the sum of the scores for each section. We played the HQV DVD using the latest version of Cyberlink's PowerDVD HD, with hardware acceleration for AMD AVIVO HD and NVIDIA PureVideo HD extensions enabled.
Both ATI's and NVIDIA's latest GPUs have no trouble with SD video playback. All three of the cards put up near perfect scores in the HQV test. In case you're not familiar with HQV, 130 points is the maximum score attainable. At 128 points, a PC equipped with either of these graphics cards plays back DVD video at quality levels better than the vast majority of set-top DVD players on the market.
We should note, however, the Radeon HD 4870 X2 did suffer from some visual artifacts when we scaled the DVD video to anything higher than its native resolution. We suspect the new DVD scaler that is part of the UVD 2 engine had an adverse affect on the specialized HQV tests. The effect was less pronounced that what we saw in our initial evaluation of the HD 4800 series, and seemed to only affect about 20% of the image through the center of the screen.
Next we conducted a test using an H.264 encoded movie trailer clip for "Beowulf" which is available for download on Apple's QuickTime HD website. The CPU utilization data gathered during these tests was taken from Windows Vista's built-in Performance Monitor. The graphs show the CPU utilization for a GeForce GTX 280, a Radeon HD 4870, and a Radeon HD 4870 X2 using PowerDVD HD to playback the QuickTime clip.
GeForce GTX 280
Radeon HD 4870
Radeon HD 4870 X2
With a fast quad-core processor powering our test system and an unencrypted HD video clip being played back, all of the cards we tested had low CPU utilization in this test. We should note that with hardware acceleration disabled, playing this video clip results in about 12% - 15% average CPU utilization, so there is a marked improvement with both PureVideo HD and UVD 2. Also note that with encrypted content, like many off the shelf Blu-Ray discs for example, CPU utilization will be measurably higher that what you see here. However, both platforms should have no trouble playing back high def digital video.
With that said, the Radeon HD 4870 X2 did consume more CPU resources than the Radeon HD 4870, but an average of 11% should still be considered low.