Even though i decided to go 6950 im still curious. How come when CF I get insanely low fps (max. 20 fps) in Crysis 2 and Dragon Age 2 when I have vsync DISABLED and get solid 60 fps when I have vsync ENABLED? I'm used to it being the other way around with my single gpu setup.
running cross fire 5850 setup with 16x/4x are 2-3 percent performance lose compare to 16x/16x crossfire set up.
I think its your mother board have problem maybe update bios?