If I play the game for a long period of time, usually around one hour 30 min the FPS drop to where it's choppy. If I quit the game and restart it's fixed. I have two computers one AMD Phenom II 965 with AMD 7950 (issue never happens,) intel Xeon 3.06 with AMD 290x. Intel runs everything at Ultra. Runs all games I have at Ultra. AMD system is at mostly High. AMD system this never happens. Intel system FPS become choppy after time. Quoting game and relaunching game fixes issue. Almost to the point that I know after hour and 30 min I have to quit game and restart. Almost seems if I timed it the stop watch would be very close to the same time ever time. Issue happens even if I leave game in main menu. Basically the game not mater what, playing or at idol, at the hour 30 mark I have to restart the game to stop the FPS from dropping.