I am Running a GTX 275, 6GB Ram, and a Intel I7 920 processor. I had the crazy stuttering issue with Nvidia.
Then i read a post about a solution, there was one with going back to the 190.62 driver, and it helped a bit. But then i read about updating to the new beta driver 195.81. And for me it removed all stuttering. Now it runs smooth on 1900x1200 with all on max plus enhanced 8xq AA.