surprisingly it never happen to me before, but only now it does. so far it happen to me on custom tracks like Daytona Rising day/night and the Talladega Dusk track I've downloaded. basically, once I get out of the turn 4, my game instantly goes from usual 40-60 fps to the insane 2-3 fps and I don't know why it happens. it also happens when I start the race itself, so once the pace lap is happening and once I exit the turn 4, the issue comes back again and kills off my fps. I don't know how to fix it. I hope anyone can relate.