One of the Faqs I read about mouse lag in Quake3 said you need to change the priority to high to get the most accurate response from the mouse, otherwise the new windows XP API or however it is set up by microsoft doesn't give the mouse enough priority and it lags... I just read it in a faq and am tired if setting it up manually each time I boot, it is listed under tasks and the setting doesnt save when I reboot...