Doing some testing with a friend.
Both have GTX680s, both have identical autoexec.cfg, both have identical ingame settings. Identical nVidia driver settings.
I run 1920x1080, he runs 1920x1200.
We stand in the same location and stand looking at the same pixel.
I get 85 FPS, he gets 130FPS.......bonkers!
Differences:
I'm on Windows 8 with the 314.09 drivers. i7 2600k @ 4.5GHz
His on Windows 7 with 314.07 drivers. i7 920 @ 4GHz
Not sure either of them can account for a difference of 45FPS.
Edit - Rolling back to 314.07 to see.
Edit 2 - Same FPS on 314.07 as 314.09.