SLI and Antialiasing

SLI can end up nearly doubling performance in some cases. In those cases we will see two 6800 GS cards deliver performance on par with a single 7800 GTX. But much more of the time we will see only a modest performance gain from SLI. Since one 7800 GTX costs about the same as two 6800 GS cards, we have to strongly recommend against going with 6800 GS SLI. If performance is desired and the money is there, the 7800 GTX is the better buy by a long shot.

We also generally do not recommend SLI as an upgrade option. The main benefit of multi-GPU technology these days is to increase the maximum performance beyond the fastest single card on the market. ATI and NVIDIA have kept upgrade cycles fairly consistent over the past few years. It makes sense to spend money on a card that will bring increased performance and more features to a system when a new generation of GPU comes out rather than augmenting an aging card with another of the same type. Another argument against SLI-as-upgrade for the 6800 GS in particular is that we have no idea how long the card will be in production.

The memory bandwidth of the 6800 GS makes antialiasing possible on most games at 1280x1024 and below. At higher resolutions, AA performance might not be where we would like. Games like Half-Life 2 will certainly run fine on a 6800 GS with AA enabled at 1600x1200. But the SC:CT and BF2 tests we ran show that the 6800 GS just doesn't have what it takes to make 1600x1200 with 4xAA a reality.

For those who wish to enable AA at higher resolutions, a beefier card would do the trick. The 7800 GT is a good value right now for those with these needs. For users with 1280x1024 panels, or who run at lower resolutions with AA enabled, the 6800 GS is a good fit.

Splinter Cell: Chaos Theory Final Words
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  • Matrices - Tuesday, November 8, 2005 - link

    I have great respect for this review and this website, but I have to emphasize I think the SLI section was extremely inadequate. You can't just bench one game barely anyone plays and then declare the issue closed. This is important becaues this card you can buy for just $200 now on the internet. So if anandtech did a thorough test of SLI and it turned out SLI beat out or tied a single GTX in Q4, D3, BF2, etc., that would be highly revealing.

    After all this card is on part with 6800 GT and 6800 GT SLI does best a single 7800GT. The difference between the GT and the GS is that you can get a GS for 200, not 270+ like a GT, so this could turn out to be a real steal of a deal. Unfortunately beyond Tech Report's more comprehensive SLI analysis I have nothing to go on...
  • AtaStrumf - Tuesday, November 8, 2005 - link

    On another note, a comparison of a overclocked GTO @ XT PE and a overclocked GS would be very interesting. :)

    I ditto that. I have an X800GTO2 and it unlocks and OCs to X850XTPE easy. That thing eats 6800GT for breakfast and is cheaper and widely available. The only problem is that it's limited edition.
  • Jedi2155 - Tuesday, November 8, 2005 - link

    Did anyone notice this on the power "consumpion" comparions ;).

    Should be consumption :).
  • Calin - Tuesday, November 8, 2005 - link

    On the end of the last page there is:
    "You can buy the 6800GS today in its eVGA forum at several vendors."
    I suppose you wanted to tell "its eVGA form"
  • Matrices - Tuesday, November 8, 2005 - link

    The SLI results you got here are the exact opposite of the ones reported by Tech Report:

    http://techreport.com/onearticle.x/8993">http://techreport.com/onearticle.x/8993

    Those folks saw a 100% increase in every benchmark with SLI using this card...

    I wonder what the heck is going on here?
  • DerekWilson - Tuesday, November 8, 2005 - link

    I did mention that sli can give almost 2x performance ... but the problem is that it doesn't happen in every game. You get consistently fast perforamnce for your money from the 7800 gtx. That was my point.
  • BenSkywalker - Wednesday, November 9, 2005 - link

    Can you try and come up with a better line? Your anti-SLI rants are looking fairly comical when looking at the 6800GS. It is less expensive then the 7800GTX by a decent amount even including the SLI mobo premium and it is almost always faster at resolutions high end users look for. I can understand you avoided running the SLI benchmarks as it makes your comments for some time invalid, but shouldn't you be able to clarify that by saying that the price/performance balance has changed in this singular instance?
  • Zoomer - Wednesday, November 9, 2005 - link

    I feel SLI is overrated, too.

    Higher mobo costs, higher psu costs, higher heat management costs (more heatsinks, fans, etc). And if you want to upgrade from that, you'll have to sell both cards.

    What is wrong with selling your current card and getting a higher end version? Is really more economical to you? Or does it just line nvidia's pockets?

    Remember, nvidia makes from the nf4 and from the extra chip sales that would otherwise be lost.
  • JarredWalton - Tuesday, November 8, 2005 - link

    The SLI tests here are only from one game (Splinter Cell: Chaos Theory). Hopefully, we can get a few more titles benched in the near future.
  • Zoomer - Monday, November 7, 2005 - link

    Page 2:

    "The 6800 GT falls somewhere in the middle of the pack in terms of power draw."
    Doesn't make sense, it had the highest and 2nd highest power draw, did you mean 6800 GS?

    http://www.anandtech.com/video/showdoc.aspx?i=2593...">http://www.anandtech.com/video/showdoc.aspx?i=2593...

    And I guess this tells us that 500W power supplies are redundant. A properly rated, quality 430 watt unit would be more than sufficient.

    On another note, a comparison of a overclocked GTO @ XT PE and a overclocked GS would be very interesting. :)

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