And a note to others: As Omophorus mentioned above, changing games to Windowed mode is the same as turning off Crossfire/SLI in most cases. Fullscreen (Windowed) also counts.
experiencing it, since i own the system is different....at least for me, when the game runs in full screen, it is stuttering and wacky frame rate. when it is on fullscreen windowed, no stuttering and frame rate is 40-60, just as it was pre 1.4 with fullscreen. So, i don't know what is going on, but something is screwy.