The GeForce 6800’s video processor is broken

We’re a little slow on the uptake around here when it comes to some news stories. For instance, various pockets of the web have been abuzz about some video acceleration deficiencies of the NV40 GPU powering all GeForce 6800-series graphics cards for a few weeks now. This morning, we received mail for TR reader Henrik S. asking this:

It seems that the current revision af AGP-GF6800 cards may have had almost
all video acceleration in hardware disabled by an internal flaw. This means that in will _not_ be fixable by a driver update 🙁 Would you look into it?

To answer Henrik’s question, we were actually aware of this problem shortly before we published our GeForce 6200 review, but it simply got lost in the mix. NVIDIA dropped 6200 cards on reviewers a few days before the card’s official launch date, and it took a lot of long hours just to get that card’s basic 3D capabilities reviewed properly. Originally, NVIDIA had planned to bust out the hoopla about the onboard video acceleration built into the NV43 GPU that powers the GeForce 6200/6600 cards, and they briefed us pretty extensively on those capabilities. However, they decided to delay that aspect of the product launch, in part because the drivers weren’t ready.

One of the things we learned during that briefing was that the video processing unit in the original NV40 chip, from which the NV43 is derived, didn’t quite live up to its billing. The NV40’s programmable video processor, you may recall, was supposed to be a dedicated section of the GPU, distinct from the pixel shaders, capable of accelerating both encoding and decoding of advanced video formats like MPEG4 and WMV. NVIDIA told us at the time of NV40’s launch that the video processing unit was unique in the GPU world, and that dedicating transistors on the chip to accelerating video processing was more elegant and efficient than using pixel shaders to handle such tasks. However, NVIDIA wasn’t able to get everything working as planned in NV40 silicon, so the NV40 video processor cannot fully accelerate WMV, just MPEG2. Instead, it has to farm out encoding/decoding work to the CPU, as GeForce FX cards did.


NVIDIA also confirmed to us that NV40-based cards do “load balancing” between the video processor and pixel shaders for some video processing tasks, although we didn’t get into the nuts and bolts of which computations were handled by the CPU, the video processor, and the pixel shaders. That’s just for decoding, as far as I know. Anand did a nice write-up about this problem, and he said that NVIDIA wouldn’t answer his questions about whether the NV40 will do any hardware encoding.

NVIDIA won’t be able to fix this problem with a driver update, obviously, since the problem is in NV40 silicon. All current GeForce 6800 cards, both AGP and bridged PCI Express (NV45), are affected, and NVIDIA gave us no indication that they plan to fix the video processor silicon in a newer revision of NV40. I expect they will simply replace NV40 with a newer high-end NV4x GPU and incorporate the fixes at that time, as they’ve done with the lower-end NV43.

At present, even NV43-based cards can’t make use of the advanced encode/decode capabilities of the video processor, because NVIDIA hasn’t supplied the world with a working driver for it yet. NVIDIA has promised an updated driver and codec software layer to make this work in the relatively near future. When we get our hands on it, we plan to test CPU utilization and the like with an NV43, NV40, and competing ATI products, so we can see the real-world impact of these problems.

Comments closed
    • Brap
    • 15 years ago

    After the FX,we get a 6800 that works,well almost…

    nVidia should work on their hardware instead of throw mud at ATI.

    • leftiszi
    • 15 years ago

    THEY CANNOT BE SERIOUS ABOUT THIS! What the hell is going on in this stupid world we live in? Refund or free replacement is a must if all of this turn out to be true! That’s the reason i bought this stupid card. Not to play DOOM3!

    • deadsoulz
    • 15 years ago

    This is one of the main reasons I bought one a 6800GT, I wanted it to help offload some of my video work, with my Digital Camcorder, They fully advertised this before launch, and stated it as a feature, I want a free replacement with the functionality working!

    • bodom81
    • 15 years ago

    Note: Certain features of the on-chip video processor will be implemented in a future NVIDIA driver release

    §[<http://www.nvidia.com/object/feature_on-chip-video.html<]§ Whish they would say what features exactly will be implemented.....

    • YeuEmMaiMai
    • 15 years ago

    just another reason not to buy a Nvidia product.

    • Krogoth
    • 15 years ago

    (Tsk, tsk, tsk)Nvidia has messed up their HTPC market sales for the NV40 series with it’s flaw in the silicon. Then again how much of the market do HTPC users comprised of? Maybe only around 10%. This problem is really a non-issue for most 6800 and 6600 users who are gamers at heart but, occationally encode/decode videos.

    Nvidia’s Personal Cinema line is still inferior to ATI’s AIW line with features and drivers. Now with this flaw in the silicon the future for NV40, NV41 and NV43 for them to be utillized in Personal Cinema line is very bleak.

    Then again slows again the great difficulty chip architechs have to endure with today’s insanity complex-chips. It’s virtually impossible to make something work without issues that weights a hefy 220 million transitiors. AMD and Intel both have minior flaws with their latest chips. I’ll sure ATI’s R420 has some minior gltiches within the it’s silicon that hardly anybody takes noitce.

      • emkubed
      • 15 years ago

      I think the market share for HTPC cards is much much lower than 10%.

      Maybe 5% of enthusuasts, which are probably 2% of the market.

    • Ryszard
    • 15 years ago

    Would it be possible to include NV30 and NV35/38 in the analysis too? If only for an interesting MPEG2 baseline. I’m sure your analysis will make their inclusion worthwhile, if you’re digging in the MPEG2 direction too.

    • opinionated
    • 15 years ago

    It would be nice if the video card could help out with my mpeg2 to wmv conversions. That takes a lot of cpu power for a long time.

    • spworley
    • 15 years ago

    Is WMV or even MPG hardware acceleration really so important? Playing a DVD quality MPG or WMV takes less than 10% of my (AthlonXP 3000+) CPU. No big deal. Hardware video decoding was important back in the days of the Pentium II where it took a bigger fraction of the CPU power, but who cares, today?

    My only thought is that perhaps the hardware decode would simply be to decrease stuttering and skips during the times the CPU load does go to 100% when you’re multitasking with a high priority process.

    To me, the hardware decode is an ignorable feature, I’d prefer them to remove it and lower the price $2.

    Edit: I tried playing an HDTV clip.. it did go to 60% CPU. OK, I see the use. 🙂

    Edit 2: Looks like the processor does work, but needs the proper drivers. I wonder if it just doesn’t work as well as they hoped? Look at §[<http://www.xbitlabs.com/articles/video/display/geforce6600gt-theory_6.html<]§

      • highlandr
      • 15 years ago

      Ah, but what about hardware encoding. That’s the good stuff right there, and why TV cards with mpeg2 encoders cost a noticable amount more than their lower-end counterparts. Plus, decoding is nice in low-power environments (laptops, HTPC) where the CPU could use a little extra help…

      • sjankech
      • 15 years ago

      §[<http://www.microsoft.com/windows/windowsmedia/content_provider/film/ContentShowcase.aspx<]§ download any of the 1080p versions of the videos that you see on this site and come back and post your results. even test the 720p to see if you can play them also. we'll see if your attitude changes after this about video acceleration on gpu's

        • albundy
        • 15 years ago

        Not when your CPU is at 100% usage, then your GPU will never be used to its full potential.

        • DukenukemX
        • 15 years ago

        Wow my Athlon Mobile at 2.4 Ghz was 70% used to play an 1080p video.

        I also have a Radeon 9500 Pro if that matters.

    • spuppy
    • 15 years ago
      • hmmm
      • 15 years ago

      Which basically says the 6800 can only do MPEG acceleration. The 6600 can also do WMV. So Scott is correct; everything else is broken. (Unless you believe that the 6800 was only supposed to do MPEG all along.)

      Am I totally out of line thinking that if this is hardware thing cards ought to be replaced? They advertise a feature of their flagship product. They say it won’t be ready at launch but will be soon after. Then they say it is unfixably broken. NVIDIA ought to be stand-up about this whole thing and replace cards for people who request it (probably most will never even notice).

      Finally, where is NVDVD available for “download” (as stated in the Inq article) on NVIDIA’s site? I see a place I can *buy* it, but I don’t really like the idea of having to buy their DVD program after I spent $400 on one of their video cards just to get one of its advertised features to work. That strikes me as slightly unreasonable. Perhaps I’m just blind and cannot find the “if you own a 6800 or whatever, download for free here…” link.

        • spuppy
        • 15 years ago

        When did NVIDIA say they would accelerate WMV though? I don’t seem to recall, and don’t feel like researching it…

        • kvndoom
        • 15 years ago

        I emailed Fudo with the exact same sentiment. The NVDA rep made it sound like you can just go and download it like a video card driver, but that’s not quite the case…

        • derFunkenstein
        • 15 years ago

        Sounds alot like the Radeon 8500 and trilinear/anisotropic together. Both sides are guilty

        • apsog33
        • 15 years ago

        I thought NVDVD came with all new nvidia cards? Maybe it’s just an EVGA thing.

          • indeego
          • 15 years ago

          I believe it’s a system OEM/card OEM thing. A few of the reviews I read of it don’t specify it either, so yeah it does seem confusingg{.}g

        • Palek
        • 15 years ago

        If you look at what else is available on the market, I think it is completely unreasonable to expect nVidia to make their DVD decoder software available as a free download. You most certainly do not see Cyberlink or InterVideo give their codecs away.

        I am not entirely sure, but I think there are some licensing fees involved with MPEG-2 codecs, so you will never see free software coming with MPEG-2 decoder plugins unless they are of questionable origin (this is why even VirtualDub can only handle MPEG-1 by default and you need a hack or a mod for MPEG-2 – the homepage of the original VirtualDub’s author has some info on this issue, I think). Windows Media Player can only play DVD’s when you have a 3rd party codec – such as Cyberlink’s – installed. The nVidia DVD decoder is also one such codec.

        I always assumed that the hardware acceleration for video encoding and decoding would be handled by the ForceWare drivers, so it should be available with or without the nVidia DVD decoder. In fact, nVidia’s own FAQ page (http://www.nvidia.com/object/decoder_faq.html#graphics) states that the nVidia DVD decoder is not dependent on nVidia’s own products and will support any video card that has the necessary acceleration mechanisms built in.

    • Gandhi
    • 15 years ago

    So I guess this is an issue when HDTV becomes more popular/cheaper? I am asking this because I have an ATI 9800 AIW and love is as far as standard TV is concerned, but was thinking of switching to NVIdia. I guess I will just wait for ATI to come out with a AIW version of their R500 card. By then I will probably switch to A64-Socket 939 and PCI-E

    • Convert
    • 15 years ago

    How serious can it be? I mean it just affects video playback correct?

    • nihilistcanada
    • 15 years ago

    Oops!
    Sad really, for me the only compelling reason to switch to Nvidia over ATI. Makes sense though as their has been no mention of this feature since the launch. But then they probably new it was messed up then anyway.

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