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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yacoub - Friday, April 27, 2007 - link
Wait, so is H264 decoding is so terrible with gaming cards that anyone who wants to watch H264 encoded DVDs or videoclips would waste the extra $$$ to get a GTS?Outside of HTPCs there's really little market for it and even for HTPC there's likely something cheaper that gets the job done just as well (8600GT?).
Let's see what NVidia does for the G80 refresh in a few months... hopefully it includes putting out a card with the spec sheet the 8600GTS should have had: 64 stream processors and a 256-bit bus.
bearxor - Friday, April 27, 2007 - link
EIGHTYFIVE
HUNDRED.
-----------------
That's the HTPC card. No one with a HTPC is going to spend $70-150 more if it performs exactly the same. But we don't know because no site seems to be able to buy one from newegg even though they've been available since last Tuesday. I guess they're waiting on nVidia to send review samples. I have a hundred bucks in hand ready to buy a 8500 but have been waiting to see how it performs with video decoding.
PLEASE!
kilkennycat - Friday, April 27, 2007 - link
The 8600GT/GTS has HTPC built-in. THe 8500GT does NOT. It apparently is a vendor-supplied option in the case of the 8500GT.Newegg has been very careful in their listings of late to include "HDCP" in their text-description of graphics cards if they are aware of it being available. However, you should also check the manufacturer's website specsheet. If no mention of HDCP there... buyer beware !!
For an example, see the BFG website and the specs for the 8600GT and the 8500GT ( Other vendor websites very conveniently hide the HDCP detail in their summary descriptions, eg: eVGA )
See:-
http://www2.bfgtech.com/bfgr85256gte.aspx">http://www2.bfgtech.com/bfgr85256gte.aspx
and
http://www2.bfgtech.com/bfgr86256gtoce.aspx">http://www2.bfgtech.com/bfgr86256gtoce.aspx
Compare and look at the last couple of paragraphs, No sign of HDCP on the 8500 spec.....
kilkennycat - Friday, April 27, 2007 - link
Ooops sorry. No edit-function for past-postings on Anandtech nor Daily Tech. ( I suggest that Anand and DT personnel take a look at The Tech Report website http://techreport.com/">http://techreport.com/ for the proper way to handle edits in comment-postings....)Anyway, I meant to type HDCP on the first line of the above posting. So anybody with a H...T...P...C requiring H...D...C...P needs to be a little careful in their choice of whether to invest in a 8500 or a 8600 card and double-check the manufacturer's spec for the magic abbreviation "HDCP". Otherwise, iirc the video decoding capabilities of the two families are identical.
bearxor - Friday, April 27, 2007 - link
Yes, HDCP is a option on the 8500. Newegg has a HDCP 8500. The gigabyte with passive cooling, perfect for a htpc.The problem is the 'supposed to have'. Who knows? I've not seen benchmarks on it. the 8600GT and GTS are 'supposed to be' the same but in this review there were some significant differences between the two. At one point the 8600gt required 8 percent more cpu power. How do I know the 8500 won't be 10-15% higher than that?
A5 - Friday, April 27, 2007 - link
Is there any chance of a review of the various PVR/TV/MC packages out there, like a comparison between SageTV, BeyondTV, Vista MCE, and a free option (GB-PVR/MediaPortal)? No one has really done anything like that since you guys did it a few years ago, and a lot has changed, especially with the advent of practical HDTV cards.ssiu - Friday, April 27, 2007 - link
Are there any image quality differences between G8600 / older NVIDIAs / ATIs / no hardware acceleration?In your previous article http://www.anandtech.com/video/showdoc.aspx?i=2923">Coming Soon to HD DVD: Silicon Optix HD HQV you talked about both ATI/NVIDIA flunked the HQV DVD tests when the HQV tests first came out, but now had improved to almost perfect score, but then they all got 0 score on the "(beta) HD HQV" tests. Has the situation improved with newest hardware+driver?
Final Hamlet - Friday, April 27, 2007 - link
It's really great to know that this GPU is better at playing back videos I would never buy because of the DRM crap on it...It's like buying a car for it's colour...
yzkbug - Friday, April 27, 2007 - link
There is still no retail version of WinDVD HD available. Any news when InterVideo is going to release one? They must be really afraid to repeat thier previous fiasco when thier master key was revoked :)ZetaEpyon - Friday, April 27, 2007 - link
Was this article written a while back or something? I have an 8500GT in hand right now.