EZ game booster does stop some applications that take up Ram and CPU power on your machine that you do not use when you play games. You can change what it stops from running, Like by default spotify is on the list if you have it. I find it does give about a 5-10 FPS boost on most games I play like CS:GO and Unturned.
Overall, I would say it works quite good. It may work even better on lower end PCs, Or older PC’s.