i would say very high, i have two setups 2600k with 580gtx and a i5 760 with a 570gtx and both setups will run ultra, only reason i say very high is because my system with the 570 on some outer lvls dips into low 40's and on the lvl that u attack from the water onto the beach when the smoke is going off it evens dips as low as 29. i would say you would be able to do very high no problem!
and the OC on the cpu doesnot matter very much. bf3 is highly gpu bound.
you might get to run even ultra settings if you disable the 4xmsaa that gets auto activated on ultra settings.
personally speaking, AA was never very important for me. if i notice aliasing in the game during gameplay, then the pacing of the game is not very engrossing.