It's true that Crysis favour's nvidia and this thread confirms it:
There's even a patch in thread to show how it sucks on nvidia cards.
I'm not expert but when single 8800gts runs better Crysis then my 2x4870 then something is fishy.And for the record Crysis doesn't scale well or did everyone forget that you couldn't run Crysis on 64-bit machines until 1.3 patch or something and it still crashes.And how the hell even next generation of cards can struggle with this game and call it self good scaling.Tell al least one review where normal PC setup runs it at 60fps I dare you.