i´m using AMD Phenom II X4 945 3.0 GHZ, Win 7 64 Bits , XFX R7 370 2Gb GDDR5 , 8 Gb ddr3 RAM
sometimes is on, sometimes it doesn´t toggle or even the options dissapears after few clicks
at times i can set to off but then it shows again enabled
my problem is also showed by another user in this topic https://community.amd.com/thread/197830 but my graphic is soported
Not all products need the Power Efficiency toggle and the R7 370 is one of them.
You should not be seeing this options and I've already reported it to the appropriate people.