Using a GTS8800 with an intel core duo, there seems to be a constant ministutter or framedrop/frameskip active regardless of gfx settings. It's as if half the frames aren't being rendered though different tools indicate normal fps. Having experienced the same issue with risen I have tried their fix (
http://forum.deepsilver.com/forum/showthread.php?t=45985, disable frame pre-rendering) to no avail. Someone suggested renaming the exe to oblivion.exe though this didn't help either. I have also tried different drivers, defragging and changing cpu affinity to a single core.