Newer drivers (300+) make game freeze when running windowed.

I recently upgraded to newer drivers in order to run steam but I have had a problem… with the 310.14 drivers I had problems where when I was running a game windowed it would often lock up (still running showing FPS counter) but keyboard input would stop working and X-windows almost goes completely unresponsive (moving around windows, alt tabbing, etc…).

It seems like it has had this since they added the change for that supposedly big performance enhancement. Its almost like games now run at a higher nice level on the core leeching all processing from everything else. Also switching X sessions was a lot slower.

Well now I upgraded to 313.18 and the problem is even worse where the game goes completely unresponsive after a while when I alt tab and stuff (FPS counter locks even). This Makes me a very sad gamer =(. It seems to work fine if I cap the framerate by enabling vsync but that introduces latency which I want to avoid. Anyone know what might cause this or an option I can do to prevent this type of behavior? I think its also what is causing steam (on certain screens) to completely lock up as well.