I just bought the game a couple weeks ago after looking at the minimum System Requirements.
http://secure.gamesas.com/forums/viewtopic.php?f=40&t=6968
Minimum, C2D @ 2GHz - Mine, Pentium E6700 3.2 (OC'd @ 3.5GHz)
Minimum, 3GB RAM (Vista) - Mine, 8GB DDR3 (Win7x64)
Minimum, HD 3850 512MB - Mine HD 5670 1GB (OC'd 920&950)
Minimum, DirectX 9.0c stuff, Mine DX11 stuff

The best I can get is 20.3FPS with the absolute minimum setting of "High" using DX9 and standard textures. DX11 with High Textures is 17.6. Both are at 1280x1024.

I'm not expecting miracles, but I do expect that my better than minimum and overclocked system would at least give me a playable 30+FPS @ High.

I have all the latest patches installed (1.9, DX11, Hi-Res) and I run a very clean system. (no bloatware or anything else running when I play games) Benchmarks - http://3dmark.com/3dm11/3401268

Are there any graphics tweaks or some setting I might be overlooking that is causing the game to run so poorly? Both Crysis and Crysis Warhead ran extremely well with factory clock settings in DX10 with the Very High settings.

Thanks.

I never actually solved the problem. I sold off my HD 5670 and bought an HD 6950 2GB instead. The game runs better now.

use this autohotkey script for low graphics settings:
http://www.gamesas.com/forums/topic34056

btw, you need minimum stable 40fps to have playable game.