The Test

We chose to test with four NVIDIA GPUs and two ATI GPUs. From NVIDIA we used the GeForce 8800 GTX, 8600 GTS, 8600 GT and the 7950 GT. The 8800 GTX and 7950 GT have the same VP as the rest of the GeForce 7 line, so they should offer fairly similar performance to everything else in NVIDIA's lineup that runs above 400MHz (remember that NVIDIA's VP stops working at core clocks below 400MHz). We included both 8600 cards to confirm NVIDIA's claim that the two 8600s would perform identically when it comes to H.264 decoding.

ATI uses its shader units to handle video decode, so there's more performance variance between GPUs. ATI only guarantees 720p or above decode acceleration on X1600 or faster GPUs and thus we included two parts in this review: a Radeon X1600 XT and a Radeon X1950 XTX; in theory the latter should be a bit better at its decode acceleration.

For our host CPU we chose the recently released Intel Core 2 Duo E6320, running at 1.86GHz with a 4MB L2 cache. As always, we reported both average and maximum CPU utilization figures. There will be some variability between numbers since we're dealing with manual measurements of CPU utilization, but you should be able to get an idea of basic trends.

We chose three HD-DVD titles for our performance test: Yozakura (H.264), The Interpreter (H.264) and Serenity (VC1). Yozakura is a Japanese HD-DVD that continues to be the most stressful test we've encountered; even on some of the fastest Core 2 systems it will still peak at 100% CPU utilization. Keep in mind that the NVIDIA GPUs don't handle CAVLC/CABAC for VC1 decode as VP2 is hardwired for H.264 decode, thus our VC1 test shouldn't show any tremendous improvement thanks to the new GPUs.

We used the Microsoft Xbox 360 HD-DVD drive for all of our tests.

System Test Configuration
CPU: Intel Core 2 Duo E6320 (1.86GHz/4MB)
Motherboard: ASUS P5B Deluxe
Chipset: Intel P965
Chipset Drivers: Intel
Hard Disk: Seagate 7200.7 160GB SATA
Memory: Corsair XMS2 DDR2-800 4-4-4-12 (1GB x 4)
Video Card: NVIDIA GeForce 8800 GTX
NVIDIA GeForce 8600 GTS
NVIDIA GeForce 8600 GT
NVIDIA GeForce 7950 GT
ATI Radeon X1950 XTX
ATI Radeon X1600 XT
Video Drivers: ATI Catalyst 7.4
NVIDIA ForceWare 158.16
Desktop Resolution: 1920 x 1080 - 32-bit @ 60Hz
OS: Windows Vista Ultimate 32-bit
The Applications Yozakura (H.264)
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  • bearxor - Monday, May 21, 2007 - link

    How come we still don't have a article or benchies on a 8500?
  • billd - Friday, May 4, 2007 - link

    It's a mystery to me why nvidia thinks we are interested in H.264 when there is so little material encoded in it. Of the shipping HD disks reviewed on the site, most Blu-Ray titles are encoded in MPEG-2 and most HD DVD titles are encoded in VC-1. Furthermore there are more Blu-Ray titles encoded in VC-1 than H.264. It would have been more helpful if nvidia had natively supported VC-1 first and introduced H.264 later. i.e.

    MPEG-2 : 121
    AVC MPEG-4 : 30
    VC-1 : 46

    HD DVD:
    MPEG-2 : 2
    AVC MPEG-4 : 10
    VC-1 : 161

    Perhaps there are some TV broadcasts in H.264 however given the low bit-rate compared to HD disks there should be little benefit offloading from the CPU to the video card.
  • SilverTrine - Wednesday, May 2, 2007 - link

    Its not really appropriate to call ATi defunct when they have folded into another company, and hardware is still being sold under the ATi name.
  • Parhelion69 - Monday, April 30, 2007 - link

    Anand, I've seen in some previous benchmarkings that software solutions using CoreAVC gave better results than hardware decoding on previous generations of ATI and NVIDIA video cards, could you make some tests to see if this behavior still applies?

    Also I'd love to see tests on older CPUs, like a single core athlon 64 3000+, to see the real help of the decoding on hardware.

    Thanks a lot, I always find your reviews extremelly helpful and professional, keep the good work up!
  • Delerue - Friday, May 4, 2007 - link

    Yeah. I agree. Indeed, some people already sugest this to the Xbit Labs review, since they missed the same things. Look here:">

    BTW, nice review, Anand. You're the guy that I really trust when we talk about hardware. In time, have you confirmed this 'I believe that only PowerDVD/WinDVD support the 8600's hardware acceleration at this point'? Ah! You talked about Intervideo forum, but I can't find it. Can you give to me the adress, please?

    Thanks and keep going!
  • Tewt - Monday, April 30, 2007 - link

    What am I missing here? Wasn't this tech introduced in the 7xxx series? Was I getting 'part' as opposed to 'full'? Or is this 'acceleration' versus 'decoding' and what is the difference?

    And I would like to throw in my two cents along with Parhelion. Just from general reading, my opinion is I keep seeing more and more raw power being thrown around with HD decoding/viewing/etc. Where is the lowest bar for watching HD with no 'hiccups'?

    I would love to see someone write a code for Linux for watching HD and we find out a 1Ghz PIII and an ATI 8500 or Nvidia 5500 would run it just fine.

    Sorry, thought I was watching HD content(games and downloaded trailers) just fine not too long ago with my A64 3200+ and Geforce 6600GT.

  • DerekWilson - Tuesday, May 1, 2007 - link

    games and downloaded trailers are much much lower bitrate than especially blu-ray is capable of. lower powered cpus and older gpus can handle these fine, its the heavy hitting stuff that is the problem.

    the 7 series did not offer full decode. nothing has offered full decode until now. so yes, you were getting part. much of the decode process was being performed on the cpu, while the partially decoded video was sent to the gpu for final processing.

    with the 8600/8500, the cpu handles aacs and i/o overhead, decrypting the data on the disk, and re-encrypting the data stream to send to the gpu. this is for aacs protected content of course. games and downloaded content won't have all this stuff going on. your hd videos will still play with less cpu intervention especially in the case of h.264 videos.
  • bigpow - Monday, April 30, 2007 - link

    don't these people ever learn?
    they f#$ked up the 6800GT/Ultra vs 6600GT with purevideo and now did it again?
  • erikejw - Sunday, April 29, 2007 - link

    I cannot find a single word on picture quality in the article hence I assume it is top notch and there is no difference at all.

    I have no hardware decoder on my system and the quality of the different software decoders
    are from ok to abysmal.

    In a cheap HTPC system a slow Athlon x2 seems to be a good fit.
    I'll build my system around one and a 8500 card.
  • DerekWilson - Tuesday, May 1, 2007 - link

    decode quality is equal to powerdvd software decode quality at least.

    nvidia will be including hd filtering/post processing for the 8600 series on par with 8800, while the 8500 may not have the processing power to fully implement all the quality features.

    we will be evaluating performance using the hd version of silicon optix hqv when finalized. and we may take a look at our beta version before that as well.

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