Sorry, if this has been brought up already, I couldn't find it anyway.
I always could run Crysis 2 in 1920x1080 on "extreme" since launch. Ever since patch 1.9 I can barely run the game smooth at "High". Even lowering the resolution doesn't do much. It's especially bad in multiplayer, where it became unplayable.
I tried most of the stuff you do in these situations: reinstall drivers, reinstall the game I even set up my system again, all without any improvement. Although I have to say singleplayer seems to run quite well even on "ultra" now.
It seems so random that I have to think this is just a bug that some players have.
My system:
Intel Quad Core Extreme Q9650
Geforce GTX 580 1.5 GB
8 GB DDR 2 Ram
Win 7 Pro 64 bit.
Maybe somebody has an idea.