Quad SLI and Purevideo

Today NVIDIA is also putting its Quad SLI initiative into action. Unfortunately, it doesn't look like they will be selling add-in Quad SLI based cards in the near future, but for those in need of such a setup will be able to find them from various system builders. Obviously this is a little at odds with the enthusiast community who prefer to build their extreme rigs themselves, but NVIDIA cites thermal, space, and power concerns not easily addressable by the individual as a reason for pushing out this hardware to system builders first. How many power supplies out there can provide enough power for SLI and CrossFire, let alone have the headroom to support four GPUs? Similarly, thermal issues could definitely be a problem in a case without good air flow.

NVIDIA would not commit to any timeframe for bringing Quad SLI to the add-in market, but they did indicate that they want the requirements for Quad SLI to be clear and readily obtainable by an individual. The landscape does have to be ready for something like this. Even if an enthusiast could put together a thermal solution to support Quad SLI, most of us don't dabble in power supply design and manufacture on the side. Unfortunately, we don't have any Quad SLI cards to test out either, but we are certainly looking into getting our hands on a system. We will have benchmarks as soon as we are able.

Quad SLI will provide a few new modes that are basically extensions of what the current SLI technology offers. Split frame rendering (SFR) will now split the frame 4 ways, and alternate frame rendering (AFR) will support one GPU rendering every 4th frame. The latter mode will provide the most benefit in games that support it as geometry processing will be well divided among the GPUs. Additionally, AFR of SFR will take each frame and split it among a pair of GPUs. Each pair then renders every other frame. This mode will be compatible with all titles that currently support AFR. Additional SLI AA modes will also be added to take advantage of up to 32x AA.

The Quad SLI is setup using what NVIDIA calls an x48 PCIe interconnect. This takes the x16 connection from the motherboard and both video cards and manages all 3 at full speed. In this way, full use can be made of available PCI Express bandwidth, both to and from the system and between GPUs.

Last week NVIDIA also launched an update to their Purevideo driver which is supposed to deliver increased performance and support, specifically for H.264 video playback. We will also be looking into updating our video quality and performance tests with the new Purevideo driver as soon as possible. The biggest change we would like to see from Purevideo is a free download from NVIDIA. Currently requiring users to purchase more software in order to get full functionality of advertised features fomr their hardware is more than a little disappointing.

Splinter Cell: Chaos Theory Mid-Range Performance Final Words
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  • redlotus - Thursday, March 9, 2006 - link

    Where the heck is the X3: Reunion rolling demo benchmark? I was all geeked when AT reviewed it and said "it will make a fine addition to our round of benchmarks." Well then when the heck are you going to start using it? I have yet to see it being used for any of the articles posted since the review.
  • DerekWilson - Thursday, March 9, 2006 - link

    We really will be including X3 in our benchmarks ^_^;;

    The benchmark does take quite a long time and we needed to optimize our performance testing in order to make sure we could get the article up for the launch.

    As I have mentioned, we will be doing a follow up article, and I will look into including the X3 demo.

    Thanks,
    Derek Wilson
  • 5150Joker - Thursday, March 9, 2006 - link

    Check out these discrepancies with Anandtech's review, boy has this site been going downhill lately:

    From your older review:

    http://images.anandtech.com/graphs/ati%20radeon%20...">http://images.anandtech.com/graphs/ati%...0x1900%2...

    Then today's review:

    http://images.anandtech.com/graphs/7900%20and%2076...">http://images.anandtech.com/graphs/7900...%207600%...


    How did the XTX Crossfire lose 11 FPS with a very mild bump in resolution? Worst yet, their editors didn't even mention which drivers they used for their review.
  • Cygni - Friday, March 10, 2006 - link

    quote:

    Check out these discrepancies with Anandtech's review, boy has this site been going downhill lately:

    Wow, its like numbers change with different motherboards, chipsets, and driver revisions. ALRET THE PRESS!
  • Spinne - Thursday, March 9, 2006 - link

    That is really odd. I'd expect the numbers to swing a little, but 11 fps is 25% of 44fps. Could they be using different benchmarks? Atleast they aren't simply using the numbers from the X1900 review and are actually retesting stuff.
  • DerekWilson - Thursday, March 9, 2006 - link

    We retested with an updated motherboard (RD580) and an updated driver (CAT 6.2).

    We used the same test for F.E.A.R. (the built in performance test).

    I'm not sure why performance would drop in this case.
  • DerekWilson - Thursday, March 9, 2006 - link

    I've been looking into this, and we also are now using F.E.A.R. 1.03 rather than 1.02 which we used last time.

    I retested the x1900 xtx crossfire and got the same results. I'm really not sure what happened with this, but I'll keep poking around.
  • munky - Thursday, March 9, 2006 - link

    FEAR is one game where the x1900's have had a big lead over the 7800's, and your results from today just done make sense. How does a x1900xtx get 59fps at 1280x1024, when the gtx512 also get 59 and the 7900gtx ges 63? Comapare it to the results from another site - http://www.techreport.com/reviews/2006q1/geforce-7...">http://www.techreport.com/reviews/2006q1/geforce-7.... At 1280x960 they place the xtx at 57fps, the 7900gtx at 46, and the gtx512 at 44, which are more inline with the results I have seen before.
  • DigitalFreak - Thursday, March 9, 2006 - link

    There is a known bug in the current drivers that causes a performance drop with the 7900GTX in FEAR. Check our HardOCP's preview, where they use the updated driver from Nvidia. FEAR scores are the same or higher than the 1900XT(x)
  • DerekWilson - Thursday, March 9, 2006 - link

    We went back and updated our performance numbers with the afore mentioned driver fix.

    NVIDIA released it to the press late in the weekend, but we felt the performance increase was important enough to retest with the new driver.

    I haven't read Scott's article at the Tech Report yet, so I don't know what driver he used.

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