[bigwrigg]

1, when you say power save feature, are you meaning the phone is going into sleep mode where the screen goes dim or off?
If so that feature is in Settings, System, Power and adjust the time for the back light to turn off and the device to turn off.
I never mess with any power / performance settings in WiFi its self.
2, I have seen this happen a few times with my 800w after we went from one form of encryption to another at my office.
I simply deleted the profile, then tunred off wifi, did a battery pull, then turned on wifi, found the router and created new settings. Now i dont have any more random disconnects.