I am running ATI HIS Radeon 5770 with 1gig on board and had the latest drivers updated by steam during installation, did a reboot before playing.
I constantly get lines flashing on the screen going all directions, it's not as bad as Arma2 but it is hard on the eyes after while.
The good news is, I have been able to play with only a little stuttering.
Guess I'll have to wait and see if ATI comes out with a driver fix