Like has been said - the volumetric fog is a frame killer, it cuts my frames in half when I turn it on. I leave it off as you can imagine.
Other than that I think the game runs surprisingly well. The resolution is set to 1280x1024, I use the drop-down to set the sliders on medium and then I turn on all the checkbox options (those with labels that is
). No AA or AF. I was surprised to get between 30 - 60 fps on my 3.5 year old computer (except the video card).
AMD FX-51 @ 2.2GHz
Sapphire Radeon X1950 Pro 512MB on Cat 7.4
2GB Kingston HyperX DDR400 RAM
SB Audigy 2 ZS