MS pronouncements to the contrary, Wim 10 has been showing up slower than Win 7 in many game benchmarks.
I have never found upgrading an OS on the same hardware to be a fruitful endeavor. Never got faster ... almost always got slower (dumping Vista being an exception) ... sometimes a lot slower (W4WGs => Win 95 was 40% slower).
I you can do a clean install of the OS (make sure to write down your product key 1st) . See tenforums,com for instructions. And then reinstall the game, this will get rid of all the flotsam and jetsam left over from the original installs / upgrades.