Im having lots of issues with my HD 6870 ,on a phenom 2 x4 955....
Besides the normal lag from being in Argentina and connecting to USA servers, i have microstuttering when playing with the latest drivers....or older ones...
This preview 3 made ALL my games stutter now (they didn't before this update)...FIFA 12, BFBC2, and even older games like CS source, left 4 dead....
I gues the best is to wait for them to release new drivers...