Pretty clear sequence of events here: teens play "Initial D" in arcade, fail to drift & crash:
http://www.youtube.com/watch?v=qUd6Z1rWGLc

Although I would blame the game not for its content but its simplistic physics

Just run FAH at a lower priority thread to keep it from interfering with games. Windows XP will do this to some degree by favoring the current application, but you can ensure it doesn't mess up your performance ever by setting it to low priority. The only concerns will then be bandwidth when downloading new Work Units and memory consumption, both of which will be acceptable if you have a good "gaming rig" and broadband.