m_filter
This variable toggles mouse input filtering. When set to "1", the values which are received from the mouse's input will first be averaged together and then that value will be used in the game. The reason for this command is that some mice had problems with sending sporadic coordinates which make the input from the mouse jerky, also when using a serial or PS/2 mouse, the Windows operating system will only sample mouse input every 25ms, that is 40 times a second (for USB mice the sample rate is 125 Hz, that is every 8 ms). When set to "1" this variable will smooth out the input but it will cause latency between the movement of the mouse and the actual response in the game. When using a PS/2 mouse it is thus first recommended to try to increase the sampling rate either by changing it via your mouse driver or by using the ps2rate program which can be downloaded at ps2rate homepage . If you are playing the game at frame rates above 40 FPS and if you can't increase the sampling rate of your PS/2 rate or if you are playing with a serial mouse it is recommended that you enable this toggle.