CPU Utilization

Of course gaming performance is only part of the equation when it comes to looking at these HDCP compliant cards, the other major aspect is CPU utilization during high definition movie playback. Today we're only able to provide a small subset of HD movie playback performance as we're only testing with a MPEG-2 encoded Blu-ray title. We're still waiting for a PC HD-DVD player which will let us test VC1 and H.264 decode performance as well, but for now we're only able to look at high bitrate MPEG-2 content. VC1 and H.264 encoded content will put more stress on the CPU and GPU as a whole, but we'll unfortunately have to wait a little longer before testing it.

Just like when graphics cards started becoming important for offloading graphics processing with games like GLQuake, we are in a kind of transition period where it is becoming necessary to also have cards that can process our video playback for us. For the past couple of years ATI and NVIDIA products have been handling video decode acceleration, but it hasn't started to be really necessary until HD-DVD and Blu-Ray came around. The complex video formats they provide require more processing power to decode, meaning that slower processors won't be able to play them back without help from a graphics card.

Right now, since Blu-Ray titles are predominantly MPEG-2, having lots of extra power in a graphics card to accelerate the decode process isn't extremely important, but we still want to take a look at how much load the cards can take away from the CPU. With this in mind we put together a benchmark, recording the average CPU utilization of a period of about one minute of Blu-Ray movie playback. The movie we used was Click, and we tested each of the cards with the exact same one-minute segment of the movie. Audio was also enabled for this test.

Here are the CPU utilization results from each of our cards.

CPU Utilization

Avg Min Max
NVIDIA Gigabyte GeForce 7600 GS 51.5 41.4 58.2
NVIDIA ASUS GeForce EN7600 GT 45.5 38.8 50.8
NVIDIA MSI GeForce NX7600 GT Diamond Plus 46.9 38.3 52.9
NVIDIA MSI GeForce NX7600 GT 45.8 39.1 51.6
NVIDIA Albatron GeForce 7900 GS 45.8 36.7 54.7
NVIDIA EVGA e-GeForce 7900 GS KO 44.5 37.5 52.3
NVIDIA Leadtek WinFast PX7900GS TDH Extreme 44.8 36.7 51.6
NVIDIA MSI GeForce 7900 GS 45.9 38.3 52.3
NVIDIA MSI GeForce NX7900 GT 44.9 38.3 51.6
NVIDIA EVGA e-GeForce 7950 GT KO 43.9 35.9 50.0
NVIDIA Gigabyte GeForce NX7950 GT 44.4 36.7 51.6
NVIDIA PNY GeForce 7950 GT 44.3 36.7 52.3
NVIDIA XFX GeForce 7950 GT HDCP 44.1 35.2 53.1
NVIDIA Sparkle Calibre 7950 GT 44.1 35.9 64.1
NVIDIA BFG GeForce 7950 GX2 46.3 36.7 53.1
NVIDIA EVGA e-GeForce 7950 GX2 46.2 39.8 53.1
NVIDIA GeForce 8800 GTX 38.7 29.7 46.9
NVIDIA GeForce 8800 GTS 39.8 31.2 48.8
ATI Powercolor Radeon X1600 PRO HDMI 40.6 28.1 50.0
ATI Sapphire Radeon X1950 XTX 36.3 28.9 44.5
ATI Radeon X1900XT 256 (reference) 34.2 28.1 39.8
ATI Radeon X1650XT (reference) 38.3 28.1 46.1


Video decode acceleration on NVIDIA GPUs is handled by the PureVideo processor, which is tied directly to the core clock speed, so the CPU utilization of each card will reflect this. The end result is that an NVIDIA card with more pipelines that is better at 3D performance will not necessarily be better at video decoding. With ATI, its AVIVO decoding is also tied to the processing power of the card, but is not quite as related to the clock speed as it is with NVIDIA. We also found that there was a bit of variance between multiple runs of the same tests, but these tests give us a general view of the CPU utilization of each of these cards.

We can see that the X1900 XT 256 gets a very low average CPU utilization compared to the other cards. Also, the 8800 GTX and 8800 GTS offloaded more processing from the CPU than the other NVIDIA cards, which isn't very surprising given that NVIDIA mentioned that the PureVideo core is a bit faster in G80. For reference, we measured the CPU utilization of the Blu-Ray playback benchmark with hardware acceleration disabled, and we got an average of 51.0%, giving us an idea of how much work these graphics cards take off the CPU. The Gigabyte 7600 GS doesn't seem to help in this area at all, and it makes sense when we consider that it's the slowest clocked NVIDIA card of the group. It would appear that a 400MHz clock speed doesn't provide enough power with PureVideo to make a difference in CPU utilization.

Even taking into account these results, CPU utilization isn't going to make a big difference between which of these cards would be better choices than others. Until we can look at H.264 and VC1 decode performance we will have to focus on other important factors to consider such as power, heat and noise.

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  • DerekWilson - Friday, November 17, 2006 - link

    We chose Click because of it's bitrate, not because or its artistic value :-)
  • msva124 - Thursday, November 16, 2006 - link

    quote:

    The fact that both the graphics card and display device must be HDCP capable, and most displays and graphics cards that people are currently using aren't HDCP compatible is a problem for consumers in general.
    Not really. The industry conforms to the the buyer, not the other way around.
  • Josh Venning - Thursday, November 16, 2006 - link

    Thanks for the comment, but the fact is that in the war against piracy, there is a lot of collateral damage.. Movie industries don't care if the consumer dislikes the fact that they have to upgrade their system in order to play the movie with the newest copy-protection standards. They only want to get rid of the pirates at whatever cost. This is why ultimately, everyone will have to conform.. or else not enjoy the benefits Bluray and HD DVD have to offer.
  • LoneWolf15 - Friday, November 17, 2006 - link

    quote:

    This is why ultimately, everyone will have to conform.. or else not enjoy the benefits Bluray and HD DVD have to offer.
    However, if people fail to adopt (or are extremely slow to adopt) HDCP and balk in enough quantity, the resulting drop in sales would likely force the content industry to rethink its position.

    Don't think that I believe this is going to happen; I believe most consumers are sheep, and they'll go out and buy what is needed. Some of them may even pitch a fit that they have to, but they'll still likely do it because they want the content more. If Jane and Joe consumers across the globe said "We won't buy it" though, I think things would change. They would have to, or the loss in sales would eventually drive the content industry out of business.

    Gives me a chance to remind myself that sometimes Sunshine/Outdoors 1.0 beats a home theater though, when the choice is available. :)
  • DerekWilson - Friday, November 17, 2006 - link

    But the industry is feeding the consumer the line that this is the only way it can be. The average consumer doesn't know or understand that things /could/ be done a different way.

    The average consumer doesn't realize what he or she is giving up by buying into the industry's FUD. Pirates don't rape artists of their money. The very studios the artists work get their first.

    It'd be great if everyone would boycott BD and HDDVD. But it's not going to happen.
  • LoneWolf15 - Monday, November 20, 2006 - link

    I agree, Derek.

    One thought...considering that this was an HDCP review, I'd enjoy seeing a followup that did some work with evaluating video playback quality. I game, but I want an all-round card solution. This explains why I got rid of my Geforce 6800 --good gaming card, video playback was average quality on supported accelerated formats, and nVidia's PureVideo (rev. 1, or should I say 0.99) fiasco drove me away from them.

    I'd be very interested to see how the current PureVideoHD and Avivo technologies square off, both in CPU usage under H.264, but also playback quality.

    And, while I know things could be done a different way, my pessimism towards the future is high. It explains why HDCP support was a requirement in purchasing an LCD panel this week. This really stinks, I'd have chosen standard-aspect over widescreen except for that (almost no 20" standard displays with HDCP; I say almost rather than none, but I didn't find any). I had to get a much bigger widescreen to make up for lack or vertical height relative to a standard-aspect display.
  • Sunrise089 - Thursday, November 16, 2006 - link

    Not always - see the record industry for the ideal example of those that do not conform to anything other than their own outdated models.

    I'm an enthusiastic capitalist, but some industries or industry groups have been unable or unwilling to adapt to the rapid pace of technology driven change in the internet era. Such groups have oftentimes fallen back upon legal attempts to force the marketplace into accepting their idea of how buisness should be done. The RIAA and the companies it represents refused to understand the oppurtunities the internet created for them, AND they refused to offer the product the consumers desired, because it didn't fit their model. The iTunes success story has forced them to sit up and take notice, and now rather than try to finally offer what customers want, they continue to wish to put the genie back in the bottle, and try to offer digital content to consumers only when it can be made 'safe' through DRM. DRM is NOT a market driven movement, it's a movement that attempts to remove one of the central features of the internet era - increased ability to steal content. Well fine, but the studios must think they exist in a vacuum because all they want to talk about is that negitive, not the positive factor of FAR lower distribution cost, and zero physical production cost. So we have all this focus on piracy protection, at huge cost to the end-user, that has essentially reduced the product purchased from a copy of the original work, down to a semi-permanant pay-per-view license, but the cost of the 'product' has remained the same.

    Tell me where the market forces are here?
  • DerekWilson - Friday, November 17, 2006 - link

    The market forces are neatly tied up and tossed out with the garbage thanks to the VERY anti-consumer DMCA (digital millennium copyright act).

    We can hardly even ask for what we want without being shot down by the DMCA.

    Sure, we still have "fair use" rights. But the problem is that we can't touch the content to which we supposedly have fair use due to the legal protection afforded encrypted content by the DMCA.

    If we were given unprotected movies, it would still be illegal to copy and distribute this content. It's almost like car manufacturers making cars that could only be driven by one person: it's still illegal to steal a car, but now the owner is restricted in his legal uses for the car. The comparison is even more accurate if there were laws in place to keep the owner of a car from circumventing the restriction to allow another person to drive it.

    The only thing that DRM does is keep us from the myriad legal uses we could have for our movies (and music for that matter) that don't fall under just watching and listenting. Or didn't you know you had any right to use that content in other ways?

    We couldn't even show you screen shots of the movie to compare image quality -- screen capture must be disabled during video playback.

    Sorry for the rant -- this stuff just really bugs me.
  • mino - Wednesday, November 22, 2006 - link

    Well, me not.

    Before , at college I didn't buy a single DVD cause I have no money to spend on unnecessary stuff.

    Now I buys some DVD here and there.
    But hell!
    To ask equivalent of $30 for a DVD in a country where average daily wage is $25!!!

    Also, to send some ***hole from RIAA analogue to saturday local middle school kids performance to have them pay $200 for singing some 30yrs old forgotten song on public area!!!
    Are they crazy? [Yes, they are.]

    I rememmber the co-called "totalitarian" communism jet.
    And I can say, in that era people had far more liberties than they have in US now.

    Sure, one can have a gun now. But he can't even sing or use some frickin publicly known math algorithm someone pattented. WTF?
    Lets' patent the wheel!

    20yrs ago we could not critisize the government here. But pretty much anything other than that was allowed(legal). From owning (registered)guns to singing whatever your mouth was capable off.

    Now we are gonna have all of the wondelfull liberties ... or, better said, the corporations are gonna have all the wondelfull liberties.


    To topic: what happens if you use analog output? You mentioned that the playback software asked for analog output when non-HDCP card was found...
  • AGAC - Thursday, November 16, 2006 - link

    I thought I was going to read an article to help me choose what hardware should I have if I wanted to playback some HDCP media.

    Gaming benchmarks? Great! So now I know that a Geforce 8800 GTX is faster then a Radeon X1600! Thanks a lot.

    What about OS settings, WinXp and Linux compatibility (is BluRay for Vista only?), monitor options, which card supports video in, why monitor manufacturers don´t advertise their HDCP compliant displays? Should I buy a desktop monitor? Should I buy an HDTV? what about all of it? So many questions...

    I read it all and still don´t have a clue.

    Sorry for the rant, guys. It´s this HDCP joke they´re playing on us all. Blockbuster video nearby has HD-DVD and BR titles and I laugh at the shelf because I want to play those in my pc and don´t know how to do it. I don´t remember having so much trouble with computer media since the days with my MSX computer and it´s cassete tapes back in early 80´s.

    Regards from Brazil.

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