In the 300 series of drivers Nvidia has removed the option to set 0 pre rendered frames. The lowest is 1, which gives ~10-20 ms added input lag. Please state how you feel about this at http://bit.ly/MYC5uJ.

The 200-series drivers still supports it, but we all know that within a near future they will not be updated and soon after there will be coming games which will be bugged with the old drivers.