Any of the 56.xx drivers caused me to lose around 10 FPS, from 35-40 to 25-30. I was using 41.09 until the clipboard bug, and I moved up to the standard 45.23 with the same FR as 41.09 and it also fixed the clipboard bug. I tried the Omega drivers and saw no difference fom the standard nVidia drivers.
BTW, Im using an FX5900 128M.