ATI's Multi-GPU Solution: CrossFire
by Anand Lal Shimpi & Derek Wilson on May 30, 2005 9:00 PM EST- Posted in
- GPUs
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.
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Panndor - Monday, June 13, 2005 - link
Lets hope that this endevor by ATI doesn't end up in the same situation at the RAGE Fury Maxx they came up with. The last time they tried this they screwed it up and then cut support for the card like it never existed.Looks promising, but I could see problems if they allow different hardware to run in a combined mode as well.
Competition is good so maybe this will bring down the price of the boards and the cards now.
vision33r - Wednesday, June 1, 2005 - link
Those 2 X850XT PE cards add up to $1000+ alone while price of 6800U are going down.I think the biggest prob is not if this works or not, is if the mainboard performance is sacrificed due to the ATI north-bridge. I don't gave 90% of the time on my system, I can't sacrifice losing system performance for gaming perf.
xsilver - Wednesday, June 1, 2005 - link
what's funny is that a few months after the xfire is released, nvidia will probably announce SLI v2.0 and then everyone will talk about how that's so coolWesley Fink - Wednesday, June 1, 2005 - link
#49 & #50 - The Uli 1573 we've seen paired with Crossfire DOES suport NCQ. this was confirmed this afternoon with engineers here at Computex. The upcoming ULI 1575 southtridge supports both Sata 2 and NCQ.We also saw demos of Splinter Cell on Crossfire with the 2.0 Shader. The demos were at 1280x1024 with all eye candy enabled. Frame rates in the various demos were 118 to 120. Since we did not have reference benches for Splinter Cell, it didn't make much sense to publish these results in the launch article. What we have seen is very promising, but we need more "hands-on" benchmarking before we can say much more.
Wesley Fink
mkruer - Wednesday, June 1, 2005 - link
#51 That is the real question to be answered. My guess is that ATI will work on a SLI board and visa versa unless there is something specifically in hard coded that prevents the second slot from being used by anything other the chipsets manufactures video card, which is highly unlikely. From the BIOS and driver standpoint the MB is either has 1x16 PCIex slot or 2x8 PCIex slots.elecrzy - Tuesday, May 31, 2005 - link
its possible to have Crossfire work on the NF4/945/955. Its just that ATI won't support them through the drivers. Sigh...kmmatney - Tuesday, May 31, 2005 - link
Does the ULi southbridge have NCQ support?weblizard - Tuesday, May 31, 2005 - link
No Sata II or NCQ support. That's all I need to know to NOT want a crossfire system.bob661 - Tuesday, May 31, 2005 - link
#47I had the Abit board with the AMD chipset on it. Worked flawlessly. I gave it to a friend when I upgraded that box and it was running until last year when he upgraded his box.
sprockkets - Tuesday, May 31, 2005 - link
26# That was the 760MPX or the dual processor chipset. Don't recall any irongate issues (that was 750, 760 was the DDR version, right?)