Core i7 Multi-GPU SLI Crossfire Game performance review
 

So once we posted our article, initially our target was to show you the difference between an everyday yet very fast Core 2 Duo based system and Core i7. Last years high-end PC against this new one. Now, before we begin, some rules: we will only use 3-way SLI (GeForce GTX 280 x3) here. Would we have used two-way SLI GeForce GTX 260 for example, this would limit the results for Core i7. See, the 260 GTX in SLI would be GPU bottlenecked. It's a state where the GPUs can't render any faster, yet the CPU still has plenty of headroom to compute. And a GPU bottleneck is exactly what we are not trying to show.

http://www.guru3d.com/article/core-i...ance-review/19