CrossFire vs. SLI

So, the question everyone wants answered is: how does CrossFire compare to SLI?

Well, it's very difficult to answer this question with no performance numbers. Obviously, if one solution outperforms the other in any significant way, pluses and minuses based on feature set fade into the background. But feature set is all we have to go on right now as we don't have final hardware in hand for a proper comparison.

One highly debated issue is ATI's claim of broader compatibility than NVIDIA. Our understanding of "compatibility" is that any title will be able to run in at least one CrossFire mode. This includes not only the performance enhancing modes, but the quality enhancing modes as well.

It doesn't seem plausible to us that ATI has found a way to split the graphics work between two cards in a more compatible way than NVIDIA. But enabling ATI's Super AA modes eliminates the need to split the work. With each card rendering the complete scene (only using different AA sample points), ATI can effectively offer something to all titles where NVIDIA cannot. Those who choose not to enable AA for these titles will likely see a trend similar to NVIDIA's performance - more than one card won't help performance.

As it is really difficult to tell from briefings, presentations, and white papers exactly where the lines of compatibility are drawn, we will simply have to wait until we get our hands on the cards before we finalize our conclusions.

Looking at all the features, if performance ends up equal or in ATI's favor, we have to consider CrossFire the more interesting solution. The flexibility of easily using multiple displays along side multi-GPU performance combined with the option of enabling higher quality AA (including rotated grid SSAA) is impossible to ignore. Add to that the ability to upgrade existing hardware without needing an exact match and we are sold.

Here's to hoping the performance of CrossFire lives up to the potential of its featureset.

Super AA Modes The Problematic South Bridge
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  • Calin - Tuesday, May 31, 2005 - link

    "ATI should be focused on the overall platform, not necessarily building up support for their South Bridge. Although we do think it is a bit embarrassing to have to turn to another chipset vendor to provide working South Bridges for your motherboard partners. It would be one thing if this were ATI's first chipset, but it most definitely is not. "
    AMD first chipset (AMD 760 for Slot A Athlon, or Irongate, I think) had also non working USB support (or very buggy). Most mainboard manufacturers offered USB thru an add in PCI card, in order not to use the one included in the southbridge
  • Googer - Tuesday, May 31, 2005 - link

    In theroy since It connets to the other card through DVI, I could use my old 9700pro in Crossfire mode with the newer card; even better is what if I could use an NVIDA card and ATI card in Crossfire! All I need is that moterhboard (if forgot the make and model) that supports PCI-e and Ture AGP! (not pci based agp)
  • FakeName - Tuesday, May 31, 2005 - link

    This is bogus, remember accelerator cards, mid-90's... poor solution then, same poor solution again... don't waste your hard earned money on this cerebral shortfall, the next gen will soon be upon us...
  • Shinei - Tuesday, May 31, 2005 - link

    Performance looks promising, sure, but I wonder what will be shown when AT gets hold of a sample for longer than a few benchmark runs--an 85% improvement at 1600x1200 seems a bit strange, particularly for hardware known for wheezing in the benchmarked game...
  • CrystalBay - Tuesday, May 31, 2005 - link

    Very sophisticated approach ATI...Hopefully the Composter doesn't turn to sh!t later on...
  • sprockkets - Tuesday, May 31, 2005 - link

    Hmmm, isn't the current SB on existing Radeon Express 200 boards buggy too?
  • overclockingoodness - Tuesday, May 31, 2005 - link

    #15: Regardless, what difference does it make? The performance would still be closer to what's presented in the article.
  • overclockingoodness - Tuesday, May 31, 2005 - link

    #15: You need to read more carefully. Notice how they said that it was the vendor's PC and not their own. So, obviously they had no choice. They had to go by whatever the vendor was offering at the time.
  • flatblastard - Monday, May 30, 2005 - link

    I was a little bummed after reading that the Crossfire + Xpress 200 would also have 2xPCI-e slots instead of just one like the current msi rs480m2-il. I was even more disappointed to here about the current state of the sb450. I thought the sb450 was supposed to fix the bugginess of sb400 which it is replacing? Oh well, no big suprise I guess considering their history in that department. So here's hoping for another save from uli.
  • bob661 - Monday, May 30, 2005 - link

    #16
    They weren't listed so I would imagine that they won't be compatible.

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