Well, I got a new computer a few days ago, and while playing FTB, it chokes on 15FPS. My old computer ran without a problem, but the GPU would overheat. It was a NVIDIA card. My new computer has a AMD Radeon HD 7470, which is more than enough to run FTB. I think the issue is because the GPU doesn't recognize FTB as a game, but I have no idea how to change that via the Catalyst Control Center.