Guys, I think found a pattern: Each time I get a reboot seems to be related to the wifi connection, like if the wifi freezes the tablet. Pay atention to the wifi settings when you get reboot / restart the tablet it's like searching the wifi connection like crazy, but, if you reboot normally the wifi it's already connected. Seems like a clue to me.
I played like 4 hours yesterday Chaos Rings. Seems like a really advanced game to me, so the stressing test is passed. It's not related to stress IMHO.