This is a better article.
https://www.rockpapershotgun.com/2017/01/25/windows-10-game-mode-explained/
ROFL.
RPS isn't exactly reputable but what I will say is that IF Microsoft are sorting the OS out from a gaming perspective that's to be welcomed, tiny improvements add up pretty quickly, this is why we OC our CPUs, realistically FPS wise it makes a small improvement but can be the difference between some areas noticeably slowing down in-game and not.