you can change it in windows. somewhere in control panel there is "mouse", check those options
EDIT: oh, sorry, i havent noticed that part. as far as i know - it works all right
rx480 scales well till 1.25V and you can get ~1450mhz. to do that - you just need to do a simple bios mod
sapphire nitro has dual bios, so even if you ruin one of them - you will be able to easily fix it