for some reason I now have really low fps in borderlands and the game is unplayable even on the lowest setting. everything is fine for about 30 seconds into a map and then the game plays like crap. I have contacted steam but they have not emailed me back and have tried various methods, every other game plays fine including borderlands 2 which I also have on steam. i5 3570k, 8gb ram, amd 6870.