I had been getting a miserable 20 - 30 fps on a pretty good rig (Phenom 2 x4 3.4 / Crossfire 6850's / 8 GB DDR3 ram) Alt Tabbed out of the game to go onto the Internet and found that when I went back into the game all of a sudden my frame rates shot up to 60 and stayed there until I went into a building. I then repeated this with the same effect. Frames down to 20 - 30 but if I alt tab out and back in they shoot up again for a time.
Anyone seen this happen? Thanks.