So the benchmarks I have seen from reviews are really just BS due to poorly set up computers. People here with overclocked 2500k's and GTX 560 tis / 5970s / 6950s are playing the game very well.
My 570GTX 2.5GB SLI Setup is getting the same FPS as your Benchmarked 580GTX SLI 1.5GB

i'm guessing Barry & Dave (My 2 Cards) are showing what they made of
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anyway bhavv he has probably turned off Motion Blur which can decrease your FPS BY Half from what i have seen @ 1920x1200p @ 2560x1600p