I'm getting a very weird issue with AO that shadows tend to flicker when objects go in front of the shadows. I have an EVGA Superclocked GTX 680. This problem is not just an issue with the game, as this happens with all of my games...
Video example - http://www.youtube.com/watch?v=FTdXh35t1-o
Video example - http://www.youtube.com/watch?v=FTdXh35t1-o