Hmm, well, if you had 60fps on 145, 30fps on 146, then downgraded back to 145 and get 30fps, then that would probably mean that's your computer and not C2 :P However, I have been noticing MY experience with running my C2 projects has been getting lower and lower FPS over time too, but I do a lot on my computer so I can safely bet it's that. Might wanna check your Task Manager and see whats up.