I am not sure if Fraps only affects FPS during recordings, but it is known to kill FPS.
I know there is an in game FPS counter, though for the moment it totally escapes me. (Call it, I accidentally hit the wrong key and suddenly saw a yellow fps counter in the middle of my action bars)
I know that Fraps kills FPS when you are actually recording video but it actually has an FPS benchmarking mode which writes to a file your FPS at either every frame or can give you an average, min and max over a period of time. Going to run this benchmark mode to get some specific numbers.