Is SLi useless with the core 2 duos

awesome, way to go nVidia, everyone is out to get intel , well, its not like it hasnt always been that way (concerning only nVidia mobos being used for SLi...

not necesarilly, it all depends on where the performance is having issues. The true gaming benefit, although negligible, is the core2s FSB, up until now AMD had the benefit with it HTT (Hyper-Transport Technology). but a texture intenive game has little or no effect on the CPU, that is because the only things really getting loaded are the RAM, HDD and GPU. SLi will NEVER, and quote me if you will, NEVER get anywhere near a 1.6x performance vs single cards, this because you are not doubling the frame rate, or cutting the load put on each graphics processor in half.. You are simply rendering frame by frame, but you still have to load everything onto each individual card: Both cards have the same loaded geometry instances, textures, lights, ect... and youve also got to figure that there is a matter of buffering that rendered frame onto the master card, and the bandwidth between the cards, which is defined by the PCI-E bus width/speed, is also a considerable limiter. Yes, the core2 will beneit overall frame rates, but it will not affect how the cards operate under SLi. the cards render al the frames they can, but in the end the real bottle neck, on games like oblivion which have a continually changing envionment, rich with geometries and textures, the Hard Drive is the ultimate bottle neck, and so is the RAM bandwith. The CPU can make a game run slower, but hardly. Core2 is not the solution to all the problems, its just blazing fast, Its the much needed leap that the CPU industry needed (looking back at the slow progress that we saw after AMD got the crown, and intel struggling with their flop, netburst). Remember, The video card is in esscence its own computer, and sli is a complement to this. SLi does not run through the CPU, its a video-video link, not video-cpu-video link as that would cause latency. Yeah, so much more i could say, but i wont...

To put this into perspective for you, i'm working at Best Buy, and we just got in a new Velocity Micro Core 2 system, an e6600 with a 7900GT, and we had it running COD2, BF2, 3D Mark 05, and an Nvidia Demo all running at the same time with awesome frame rates, and the CPU usage didn't breach past 75%.
Edit: This was on a 20" NEC Monitor by the way.