Partly based on driver Rockstar try to throw the ball on Ati and Nvidia but they have responsability...(or else why trouble with both Ati and Nvidia ?)
Personally i wanted to use the new beta driver (not only for aa but also because of a little boost (or so it seem) but with 180.XX i can't modify fan speed (unless using Rivatuner wich i don't like) Personnally i still use the 17X.XX (178.24) and they are stable(but no AA)