Thats what im thinking, something is def awry in my sh*t. But damn 2 in a row? And straight out the box too before I even install any apps! Going to get another replacement tomm.
that's good. at least they're giving u good service and working with u. Samsung is a standup company. I have no idea man. WiFi is better on the battery than using the cell radios, try turning mobile network data OFF while on WiFi, the phone is probably trying to run the two data receivers/transmitters at once.
You will still be able to text and receive calls because that's a separate radio ("2G") and all the data will be over WiFi, rendering HSPA+ unnecessary except when away from WiFi
try turning the screen on Auto, not keeping it at a certain setting, and turning the HSPA+ 4G off (if AT&T's 3G is fast enough to live with)