Hey!
I have a pretty old setup with two GTX 460 cards configured in SLI and it works fine when playing vanilla BF3.
While running the game from the VU launcher, I noticed the big fps difference and went to check my gpu temps and saw that only one gpu is under full load.
I have checked the nvidia control panel and SLI was enabled.
This issue makes the game unplayable for me, because the fps difference is very noticable while playing on a 120 HZ monitor!
Any help would be appreciated!