In the previous section, I mentioned about the bitrate limitations of the GT 430 when decoding 1080p H264 clips. NVIDIA confirmed that the GT 430 couldn't decode 60 fps videos at 80 Mbps. This piqued my curiosity and I tried out a few experiments to find out whether bitrate limitations exist for the usual 1080p24 videos on both the GT 430 and GT 520.

The DXVA Checker benchmark was repeated for all the bitrate testing files found in the NMT test files upto 110 Mbps.

GT 430 / GT 520 Bitrate Limitations - 1080p24

We also created our own suite of bitrate testing streams at 1080p60. Running them through the DXVA Checker benchmark yielded the following results.

GT 430 / GT 520 Bitrate Limitations

The results are presented in a bar chart above (A line chart would have made much more sense, but the outer values get placed only for bar charts in our graphing engine). For 1080p24 streams, we find that the GT 430 is unable to keep up with the real time decode frame rate requirements at 110 Mbps. For 1080p60 streams, the limit gets further reduced to somewhere between 65 and 70 Mbps. The GT 520 has no such issues.

The above testing is only of academic interest, since there is no real 1080p24 content at 110 Mbps. Even 3D Blu-rays max out around 60 Mbps (and that includes the audio stream!), so users shouldn't really be concerned about this bitrate limitation of the GT 430.

The GT 520's scores above are more interesting. Even the high end GPUs such as the 460 and 560 are unable to achieve that frame rate. The answer was buried in the README for the latest Linux drivers. The GT 520 is the first (and only GPU as of now) to support the VDPAU Feature Set D.

We asked NVIDIA about the changes in the new VDPAU feature set and what it meant for Windows users. They indicated that the new VPU was a faster version, also capable of decoding 4K x 2K videos. This means that the existing dual stream acceleration for 1080p videos has now been bumped up to quad stream acceleration.

Though the GPU can decode 4K videos, it is unfortunately not able to output it through HDMI. Despite the HDMI controller being advertised as HDMI 1.4a, it doesn't implement the 4K x 2K resolution part of the standard. The lack of HDMI sinks which accept that resolution is another matter, but that should get resolved in the next few years.

Despite the GT 520's advanced VPU engine, the lack of shaders limits its post processing capabilities. With all post processing options enabled, the GT 520's GPU load was always between 60 and 80%. The memory controller load (DRAM bandwidth usage) was between 20 and 40%. Despite the headroom apparently available, NVIDIA indicated that there weren't enough shaders available to implement the more advanced deinterlacing algorithms.

DXVA Benchmarking Software for HTPCs : LAV Splitter and Audio Decoder
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  • fixxxer0 - Sunday, June 12, 2011 - link

    that arrangement of cards slightly resembles a swastika Reply
  • Anand Lal Shimpi - Sunday, June 12, 2011 - link

    Thanks for the heads up, it honestly didn't cross our minds at all but now that it's been pointed out I can completely see the resemblance. Needless to say we've removed the offending image and I'd like to apologize to anyone who was offended.

    Thank you guys for catching it so quickly.

    Take care,
    Anand
    Reply
  • fb39ca4 - Monday, June 13, 2011 - link

    If people want to jump to conclusions, let them. The swastika means many things, if you want to associate it with Nazis then go ahead, or you could associate it with the religion Jainsim, which it happens to be a symbol of. Your interpretaion of the image affects no one, there is no reason to make a big deal over it. Reply
  • fixxxer0 - Monday, June 13, 2011 - link

    lol... i made no connection to nazis or anything... nor said i was offended.

    i just pointed out a resemblance i noticed as a matter of fact.
    Reply
  • tzhu07 - Sunday, June 12, 2011 - link

    Yeah, time to change the Nazi reference. Reply
  • qwertymac93 - Sunday, June 12, 2011 - link

    The indians(the asian ones...) have been using Swastikas for centuries before the nazi party was even thought of. Just sayin'. Reply
  • jwilliams4200 - Sunday, June 12, 2011 - link

    It is unfortunate that there is such an over-reaction to something like this. Besides, the swastika symbol is and has been used for many, many other purposes than representing Nazis:

    http://en.wikipedia.org/wiki/Swastika
    Reply
  • Souka - Monday, June 13, 2011 - link

    True as it may be that fact remains that if some one says:

    "Hitler"
    Most people think of Adolf

    "swastika"
    Most people think of Nazi

    I'm of Jewish decent... the pic didn't offend me in the least bit, nor my friends.

    Jusy saying.... ;)
    Reply
  • Gnarr - Monday, June 13, 2011 - link

    people should be thinking of Nazi's and Hitler anyways, it reminds everyone not to make that mistake again.

    I see no harm in accidentally arranging something in a Swastika :p

    and on that notes.. There is a company in my home country that has been using the swastika as the company logo for over hundred years:
    http://martasmarta.blog.is/users/1d/martasmarta/im... ;)
    Reply
  • L. - Tuesday, June 14, 2011 - link

    Unfortunately it does not.

    The way the western world depicts adolf hitler, nazism and everything surrounding that part of history is far from reminding anyone not to make that mistake again, as the main message is "nazi evil, hitler evil, us good guys, us not like them".

    Anyone ever wondered what difference there is between Gestapo and the Patriot Act ? - oh right it doesn't target jews so it's fine ... lol
    Reply

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