Video Card Roundup - DVD Quality, Features & Performance - October 2000

Here's where things begin to get interesting. The WinDVD 2.2 player we used as the Default Decoder in this test took advantage of the ATI's hardware iDCT and HWMC and thus gave ATI the lowest CPU utilization numbers.

The Savage 2000 wasn't too far behind, however what was odd about the Savage 2000 was that the test system's CPU utilization was higher when decoding a 6Mbit stream than it was when decoding a 9Mbit stream, and this phenomenon was reproducible.

The Matrox and 3dfx cards, without any sort of Hardware Motion Compensation pulled up the rear, but what's truly interesting were the NVIDIA numbers.

As we mentioned before, the GeForce was the first NVIDIA chip to boast HWMC, however as the Video2000 test shows, the CPU utilization on the GeForce (as well as the GeForce2 and GeForce2 MX) was identical to that of the TNT2 which doesn't have a HWMC engine. So why is the GeForce with HWMC taking up just as much CPU time as the TNT2 without HWMC?

Apparently, most DVD players have two modes of operation: strict DirectShow compliance for WHQL qualification, and a Private mode for vendor specific operations. Such operations may include enabling features such as HWMC or iDCT features. It turns out that Video2000 is a DirectShow only benchmark, meaning it forces the decoder into that first mode of operation, which is obviously fine for ATI and S3 since their hardware acceleration is taken advantage of and it also doesn't carry any meaning to 3dfx and Matrox who don't have any hardware assisted playback, but it does pose a problem for NVIDIA. So according to NVIDIA, the benchmark is at fault and HWMC does actually makes a difference on the GeForce, GeForce2 MX and GeForce2 GTS cards.

The only way for us to confirm this was to fire up a copy of WinDVD 2.2 and try playing some DVDs. We used a Celeron 366 for these informal tests as we wanted to make sure that the differences we would see because of HWMC wouldn't be so small that they would be ignored. Using Wintop to monitor CPU utilization during playback, NVIDIA claims were substantiated as the TNT2 consistently was 10 - 20% higher in CPU usage than any of the GeForce cards. However without iDCT support in hardware, the ATI Radeon (as well as the Rage 128 and Rage 128 Pro) still boasts lower CPU usage numbers.