That is what I am thinking, but I am trying to find some hard evidence.
Here is how my EVGA GTX 460 768MB scale in SLI @ 1680x1050 (left - single card, right - both cards):Crysis WarheadUnigine HeavenAVP Benchmark
Needless to say, I just love them :-)
Rest of the system:
I7-930 @ 3.78
ASUS P6T Deluxe V2
6GB Mushkin Blackline DDR3 RAM
Silverstone 850W 80+ Silver PSU