Nowadays, a Win 10 licence is associated with a Microsoft Account, not with a particular computer. So, you can swap out EVERYTHING, and still re-activate your windows (Provided you have set up a Microsoft Account). Personally, I like to re-install when I get a new motherboard, so that old apps and utilities that I installed (and have now forgotten about) are cleared away. Since you are just upgrading your CPU, there is no need for this. Everything will work just fine. (You do have a legal copy of Win 10, don't you ?)