Upgrade gpu.. Crysis still not working as well as it should..

hey guys.. im new here, just joined today  
anyways, last week i went out and bought a Powercolour ATI Radeon 6850 HD to upgrade from my old nVidia 9500GS.

my specs are now:

Q6600 Quad Core running @ 2.4GHz
6GB of RAM
Powercolour ATI Radeon 6850 HD
550 watt Coolermaster power supply
Windows Vista x64

First thing i do is install crysis, because i didnt bother with my old video card. I run it in a 1680x1080 window, set everything to very high (except for Post processing which i set to just "high), and run the game... and it won't run at a respectable fps. once a shootout starts, or i get into a vehicle, or zoom in with my binoculars, the fps drops to the 20s and on really intense moments it drops to the 10s...

I was tremendously dissapointed with this performance.. what can i do? Is it my CPU bottlenecking? Will restoring my system to factory settings (I bought a stock computer) help?

EDIT: The performance not being as good as it should be is not specific to crysis- something like Empire: Total War does not run at 30+ fps with high settings, and i have to run Bulletstorm in a window with no AA and Post Processing turned to Medium in order to have playable FPS, and it still probably isnt above 30.