Same problem (using WinXP) here for over a year - speeds up of its own accord and becomes unplayable. G5 and Habu show same problem. It only happens in Q3 E+. I wondered whether my Gigabyte P635 DS3 mobo's usb ports were the issue but as I said it only happens in Q3. I have tried two graphics cards (ATi 1900XTX and Nvidia 8800GT). I use a basic config. I have reinstalled WinXP and Q3. Makes no sodding difference atall! It really does make Q3 unplayable - I spend most of my time in a game battling the mouse's behaviour rather than trying to win the game. Often I leave a game early since the mouse wins!! Has anyone got any ideas as to how I might overcome this? I have seen a few posts on here showing the same issue...

I have a mx518 and i wont lie, i get nothing except errors and bit pain in the ass from the mouse. Always changes sens, does some stupid acrobatic moves...

Flex, thanks for the response and name reminder. I'd not seen the mobo for so long I'd forgotten it! Whatever, when I reinstalled WinXP, I updated the Intel chipset drivers; I have just done so again to the latest and again no solution. I appreciate you have the same mobo but maybe there's a difference in version or firmware or some component. I have a mind to go SLI so a new mobo might help.