Pickers said:
Off topic a bit, but can anyone tell me why (in all my years of gaming) I suffer with mouse filtering? Its only if I'm strafing and turning, the screen jumps. With any fps, I head straight for options and look for mouse smoothing or filtering.
Why am I plagued with this curse? It has happened on all my systems since I got my first intellimouse (serial) up to my current system which has a logitek desktop wireless combo.
Mouse filtering was initially implemented in Quake because at the time, USB didn't exist and by default mice used a ~40hz refresh rate (ps2/serial). Basically this caused unsmooth, jerky movement especially at high framerates due to the mouse position only being updated 40 times per second.
Mouse smoothing/filtering basically works by taking an average of the mouse position over the frametime and smooths out the movement.
However, filtering is fundamentally bad because there is an inherent increase in mouse latency (frametime/2) by using it. If you have 50fps, this means that you have a 20ms frametime, and hence using mouse filter gives you a 10ms increase in effective mouse latency. Doesn't sound much, but in a fast paced FPS, it all adds up.
When using modern mice, with polling rates of >100hz (usb defaults to 125hz and can be increased to 250/500/1000hz, ps2 should be increased to 200hz), there really shouldn't be any need to use m_filter. The very small reduction in mouse smoothness is more than made up for by the more responsive mouse, once you get used to it.
IF you are using your mouse via the ps2 port, it might be worth checking what the polling rate is set to - if it's at default, it's probably not at 200hz.
Bottom line is: Try and get used to playing without mouse filter, as this will reduce lag.