Windows 10
As most know Windows 10 has many nice new features, newest drivers and etc. BUT it does want to do updates, interact with servers and etc which may affect the amount of system resources available for your game. I've found this nifty little software/freeware package that gives you a quick and simple control panel to turn everything off that might affect system resources:
http://www.oo-software.com/en/shutup10
The folks who make it have this to say about it:
O&O ShutUp10 means you have full control over which comfort functions under Windows 10 you wish to use, and you decide when the passing on of your data goes too far.
Using a very simple interface, you decide how Windows 10 should respect your privacy by deciding which unwanted functions should be deactivated.
O&O ShutUp10 is entirely free and does not have to be installed – it can be simply run directly and immediately on your PC. And it will not install or download retrospectively unwanted or unnecessary software, like so many other programs do these days!