Running on a E6600, X1950 Pro 256mb (Cat 7.2), 2GB PC6400, X-Fi. Settings at 1280x1024, grass shadows off, textures up full, no AA/AF (didn't seem to make a difference), sun shadows on, grass density to about half and dynamic lighting on. Runs well for most of the time, but now and again it will lag and drop to about 20fps for a few seconds and then be ok. Quite annoying, gonna keep playing about with the settings, see if anything changes.