For me i could not play BF3 with CF Because after ten mins i would start to get freezing and stuttering ,Switched of CF and was smoother not perfect getting round 49 to 50 fps that was it .And in the beta setting for gfxs was not working right ,Just dont get it if you say some of your friends are using CF with 5870 and was having no problems then i must have some thing wrong with one my cards BF3 .Just hope there ok in full game ,But just see on twitter theres not going to be any drivers that will run better for BF3 on ati untill the 31st oct .
I had the same thing on metro, where would get stutter after few mins with xfire on - but no such problem in caspian. The problem had fixed itself when I went back on metro 2 days later though.