I think its time for me to wit for G80 and R600.
Quad SLI is out of its time, just like the bow-and-arrow thing when the powder came.

I'm curious to see how 4x4 from AMD/ATI stacks up against the Quad SLI system from Nvidia. Hopefully it wil do better then this current sollution, as quite clearly the X1950XTX CF outperforms it way too often.

The slow memory speed on the GX2 is plain stupid, its a lowly 1,2ghz, my 7900gt runs at 1.52ghz on the ram easyi.If nvidia were to clock it at a decent 1.6-2.0ghz, it will win easily.

OMG . /

ATI FTW. crossfire RAPES nvidia solution

nVIDIA have done nothing in past 6 months to improve their QUAD SLI, They should stop Advertising to make people buy QUAD SLI solutions. thats a RIP OFF.

nVidia spent a lot of time promoting Quad SLI as a technology really only suited for large 30" monitors, as at lower resolutions 1920x1200 down, it offered little or no performance improvement. How did you manage to miss this ? You should read the article on Guru3D, when they test Quad SLI on a Dell 30" TFT and come to the conclusion its a waste of money if you run on anything less. I work for a systems integrator that builds both Crossfire and SLI gaming systems. We have know about this since the early days of Quad SLI.
I hope you revisit this article and restest at 2560x1600 which is where Quad SLI generally has some value.
I'm no nVidia fanboy. The company I work for gets much better support from ATI and I have a Crossfire system at home. I'm just really dissapointed a site with your reputation managed to miss the point so badly.
You need monster resolutions to get any benifit of QUAD GPUs.