same here : usually xfire and wegame.
for frameratedisplay i use fraps.
When playing the witcher i accidentally hit a keystroke which made my framerate drop horribly to a constant 30fps.
so i thought the witcher was buggy.
after playingg for an hour / 1.5hours like this , things went wrong.
seems like i made a movie taking a whopping total of 40GB
I disabled this feature in fraps.
So i really hate fraps for this reason and is no better imho for displaying the FPS.
In most games (online) there are commands to make movies using the game engine.

FRAPS limits the game to the recording speed it is set to, if your computer can handle it.
I have no problem at all recording with FRAPS at 30fps (hence the game runs at 30fps). There are some tips and tricks to get better performance on FRAPS and one of them is having FRAPS record to a different HD then what the game is running on.