I have the same issue with my Razer Deathadder 3500 - except that I don't even need to unplug the mouse for the silly Razer drivers to reset my System Preferences mouse sensitivity - very annoying.
The other problem I have is that when scrolling down on webpages/documents using the mouse wheel, it will suddenly flick UP to the top of the page or up half a page - or sometimes down by two pages, meaning I can't use the scroll wheel at all in anything other than games - This problem was reported several times, but has persisted through numerous driver updates.
Razer just can't get their Mac drivers right - or even usable - I'm afraid ... 🙁