Love this app This app came preinstalled in resurrection remix ROM android v.6.0.1 for my sgs4 m919. With this app many if not all is possible to do. Simple to use friendly u.i. best I've used by far hands down and every option works flawlessly. If your into experimenting/tweaking out of curiosity like me or just want to set cpu freq  GPU freq  etc this is the app or You.
January 21 2016