Scaling and Performance with 3-way SLI

As we’ve explained, we had a great number of issues in testing 3-way SLI and Quad SLI on our 790i board. We couldn’t even get 8800 Ultra Tri SLI to work, as it draws so much power in addition to being finicky in the first place. We were able to get some numbers run on Crysis and Oblivion.

Here is a look at performance scaling with both; we’ll look at comparative performance further below.

These numbers were run on the 790i system and we absolutely did leave VSYNC on its default setting. Performance differences between one, two, and three 9800 GTX cards were more compressed when we force VSYNC off in the control panel.

Here is how Crysis stacks up in a direct comparison with the major competition (except for the 8800 Ultra configuration which we could not run).

9800 GTX 3-way is absolutely playable at 1920x1200 with Crysis when using Very High settings. Clearly Quad SLI leads the way here, but for $300 less, that’s not a bad deal if what you want to do is play Crysis at 1920x1200.

The delta between Tri and Quad is lower here. In both cases, two 9800 GTX cards outperform a single 9800 GX2. While the 9800 GX2 can be plugged into any system, NVIDIA still wants to sell 790i platforms. If you’ve got or want an NVIDIA based platform, you get higher performance for the exact same price by going with two 9800 GTX cards over a single 9800 GX2.

With the hassle of huge power supplies, cooling, etc. associated with Tri and Quad SLI, our money for maintaining value with a high end solution would have to fall to the 9800GTX SLI set up. 3-way seems to have some problems at the moment as well, as we ran into one large issue in one of the only two games we tested. Oblivion has some graphical issues that we document here on YouTube.

Crysis, DX10 and Forcing VSYNC Off in the Driver Once Again, The Rest
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  • Jangotat - Friday, April 18, 2008 - link

    The way they're setting this up is great but they need to fix a few things 1 use a 790i Asus motherboard 2 use OCZ 1600 platinum memory 3 let us see some benchmarks with 3-way 8800 ultra cards that would be sweet

    Platinum memory has custom timings for asus, and asus doesn't have issues like EVGA and XFX do. And we really need to see the 3-way ultra setup to see what's really the best for crysis and everything else

    You guys could do this right?
  • LSnK - Wednesday, April 2, 2008 - link

    What, are you guys running out of zeros or using some ancient text mode resolution?
  • Mr Roboto - Thursday, April 3, 2008 - link

    Derek, you say that a 25% decrease in performance resulted from disabling VSYNC in Crysis and WIC. However you then say in the next sentence that performance gains can be had by disabling VSYNC? Maybe I'm misunderstanding?

    "Forcing VSYNC off in the driver can decrease performance by 25% under the DX10 applications we tested. We see a heavier impact in CPU limited situations. Interestingly enough, as we discussed last week, with our high end hardware, Crysis and World in Conflict were heavily CPU and system limited. Take a look for yourself at the type of performance gains we saw from disabling VSYNC".
  • Evilllchipmunk89 - Wednesday, April 2, 2008 - link

    Seriously what about the AMD 790FX board? you will test the Nvidea cards on thier "home platform/790I" platform, But what not the ATI cards home platform. Obviously you can get more performance if you had the 790FX board that was made more specificly for the Radeon3870s
    where you can tweek more aspects of the card. In an earlyer review you showed us that with nothing changed but the board the 780I outperformed the skulltrail on the Nvidia cards but you wint even mess with the ATI boards
  • just4U - Tuesday, April 1, 2008 - link

    I dont quite understand why they just didnt go with a 512bit interface like on the X2's. That's what I was expecting anyway.

    One thing that has me surprised. I was checking my local store on the web for "new arrivals" (a feature where new listings appear daily) and saw the GTX and was thinking hey wait .. Annand hasn't even reviewed this yet and it's in stock???! wow. I imediately came here and there the review was :D So nvidia is trying to stay on top of the hard launch which is nice to see but mmmm.. still troubled by that no 512bit interface. To me it still seems like a GTS/512.
  • 7Enigma - Wednesday, April 2, 2008 - link

    And yet the GTS wasn't included in the review...
  • deeznuts - Tuesday, April 1, 2008 - link

    It's actually "lo and behold" and I'm not even sure it's being used right. You propably are, but essentially you're saying, "look, see, I looked, and saw ..."
  • Olaf van der Spek - Tuesday, April 1, 2008 - link

    So what is the cause of the vsync issue? I don't see an explanation of that.
    It'd be interesting to know why performance drops with vsync off.
  • finbarqs - Tuesday, April 1, 2008 - link

    Haha Happy April Fools day!
  • prophet001 - Tuesday, April 1, 2008 - link

    you guys write some nice reviews on this website but the visuals are a little lacking. i guess when i read an RSS feed that talks about 9800 gtx triple SLI then i kinda expect to see at least a picture of a mobo with 3 cards on it and a uranium iv. i know, it's about the results, but more neat pictures would be nice :)

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