NVIDIA GeForce 8600: Full H.264 Decode Acceleration
by Anand Lal Shimpi on April 27, 2007 4:34 PM EST- Posted in
- GPUs
Power Consumption
The reason that a handful of execution engines within a $150 graphics card can be faster than even some of the most powerful desktop microprocessors is because of the use of specialized logic designed specifically for the task at hand. NVIDIA took this approach to an even greater degree by effectively making its BSP engine useful for exactly one thing: CAVLC/CABAC bitstream decoding for H.264 encoded content. Needless to say, NVIDIA's approach is not only faster than the general purpose microprocessor approach, but it should also be more power efficient.
To measure the improvement in power efficiency, we outfitted our test bed with a GeForce 8600 GT and ran the Yozakura benchmark with hardware acceleration enabled and disabled. With it enabled, the 8600 GT is handling 100% of the H.264 decode process; with it disabled the host CPU (an Intel Core 2 Duo E6320) is responsible for decoding the video stream. We measured total system power consumption at the wall outlet and reported the average and max values in Watts.
At idle, our test bed consumed 112W and when decoding the most stressful H.264 encoded HD-DVD we've got the power jumped up to 124.8W. Relying on the CPU alone to handle the decoding required 8% more power, bringing the average system power usage up to 135.1W.
Surprisingly enough, the difference in power consumption isn't as great as we'd expect. Obviously system performance is a completely different story as the 8600's hardware acceleration makes multitasking while watching H.264 content actually feasible, but these numbers show the strength of Intel's 65nm manufacturing process. We do wonder what the power consumption difference would look like if a CPU manufacturer was able to produce a CPU and a GPU on the very same process. With AMD's acquisition of ATI, we may very well know the answer to that question in the coming years.
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PrinceGaz - Friday, April 27, 2007 - link
Copying a movie from an optical disc (DVD/HD-DVD/Blu-Ray) to your HDD is perfectly legal as it does not involve interfering with the protection on those files, all you are doing is creating an image-file on your hard-disk which contains all the necessary data on the optical-disc. The image-file can then be mounted with suitable software and played as normal in your preferred media player, with the media-player software handling the decrypting just as it would with an original disc.It's ripping the movie that contravenes the DMCA as that is the step which involves removing the encryption from the data. Ripping can be done either direct from the original optical disc or from an image-file on your hard-drive, the only difference is that creating an image-file first is an extra step to be performed but on the other hand it simplifies what is involved with each stage and means the only task being performed while reading the original disc is a straight copy to the hard-drive. Having an image on the hard-drive also saves a lot of time if more than one attempt might be needed to perform a successful rip.
On topic, once quad-core CPUs are mainstream in a year or two (with octal-core arriving at the high-end), H.264 decoding on the GPU will be irrelevant really-- nice to have but of no real importance, rather like how the Pentium III and original Athlon rendered hardware MPEG2 decoder cards obsolete.
Ard - Saturday, April 28, 2007 - link
Well (and don't get me wrong, I hate the DMCA, believe me), your argument would arguably fail under the strict language of the statute. The DMCA defines circumvention as "descrambl[ing] a scrambled work, decrypt[ing] an encrypted work, or otherwise to avoid, bypass, remove, deactivate, or impair a technological measure, without the authority of the copyright owner". A direct copy would probably be viewed as avoiding CSS/AACS/etc. since they exist for the sole purpose of preventing you from making a copy. I personally think your argument is more than valid because you still need a media player to decrypt the image file, but you know content providers would argue the exact opposite.smilingcrow - Friday, April 27, 2007 - link
"On topic, once quad-core CPUs are mainstream in a year or two (with octal-core arriving at the high-end), H.264 decoding on the GPU will be irrelevant really-- nice to have but of no real importance, rather like how the Pentium III and original Athlon rendered hardware MPEG2 decoder cards obsolete."I thought it was the implementation of hardware assist of MPEG2 decoding on GPUs that was the boon for DVD playback on PCs back in the day with ATI being the pioneers!
It’s still useful to have this feature regardless of quad cores from the perspective of lower power consumption, lower CPU heat output which is easier to cool quietly and better multi-tasking abilities. It’s a niche feature but for people who use it it’s something for nothing especially with the 8500 GT supporting it. Gigabyte have a passive 8500 GT that supports HDCP for $100; my next card I think.
yyrkoon - Friday, April 27, 2007 - link
SO, what you're saying is that: You can watch a HD-DVD from HDD, you just can't put it there ? lol, reminds me of one of the laws Canada supposedly had for a while, something similar to: you can download all the pirated software/media you want, you just couldnt store it on any form of media . . .Anyhow, I wonder how long AMD/ATI is going to stay silent, it seems a good bit of time since we've heard anything from them, at least, in the form of a review. Not that I miss all the fanboyistic comments . . .
BoberFett - Friday, April 27, 2007 - link
The power consumptions graphs show Peak lower than Average...Anand Lal Shimpi - Friday, April 27, 2007 - link
Fixed :)Cascavel - Friday, April 27, 2007 - link
I ask out of ignorance, but why did you not try the NERO software for HD playback - I think it is an add-on to NERO 7 / Showtime 3 ?Anand Lal Shimpi - Friday, April 27, 2007 - link
Great question, but I believe that only PowerDVD/WinDVD support the 8600's hardware acceleration at this point. I will double check :)Take care,
Anand
Hulk - Saturday, April 28, 2007 - link
The Showtime 3 release notes says "nVidia decode" a few generations ago. Perhaps they have updated it or maybe it will work. If you could test with Showtime 3 that would be great.Cobra Commander - Friday, April 27, 2007 - link
I wasn't expecting it to be this dramatic. Nice. Bummer the GTX doesn't have this tech though. :(