Thus phone is realy awasome with great specification. Many of them has said that it is having heating problem. First l also experince same but after upgrating to miui 7.1 version all problems got vanished dont think just got for it. It is not normal but I read over net that ther are fixed forit. Its mentioned that media server consumed lot of power. So if ther any mkv file in yor phone memory/sd card memory; remove and try
Also I have aqustion for you. How is gps lock in this phone in this withinternet or without internet.