go back to ccc panel 3d game settings and select default.
everything else will be controlled in game...
set the game to max settings then turn down fsaa to x2.
on your system you should expect 30fps minimum in most areas. underground you may have to turn fsaa off to stay above 30fps.
crysis is a demanding game. probably 1 of the most demanding gfx wise.
the real issue is the cpu usage because it only uses 2 cores in real terms it may bottleneck on a cpu that has poor single threaded performance when pared with a high end gfx card ...
there are some real poor optomizations that were back in the day thought to be cutting edge, and these are what cause the problems on bigger machines.
so with crysis, no matter how big your machine you will always have lower performance than you think you should have.
modding will go some way to relieve the issues but then you wont be playing crysis.