It is obviously your mouse sensitivity, replace x by what you want. I highly recommend to use 1, but some people prefer -1, so pick the one you prefer. 1 corresponds to di/raw mouse, while -1 is win32 mouse. \in_mouse x where x may be equal to either 1 or -1. However, I struggled a lot against Quake 3 to find a satisfying configuration.
Having a good mouse configuration is essential in any fps game.
