Are you having problems with lagging or jerky mouse scrolling / movement in Firefox?
I played around with my mouse for quiet some time in Windows Mouse Settings before I found a simple solution in Firefox it self.
In Firefox, go to Options and under the Advanced tab, General tab make sure Use smooth scrolling is ticked and that should fix your issues, I know it did for me.
If it doesn’t take place right away you night have to restart Firefox
That is all that is required.
Actually I have noticed that this still doesn’t fix a few web sites that have a lot of media or are just poorly built / developed.