Lol, never buy a device with 810, unless you plan taking ice-pack with you all the time. Even version 100 of 810 will overheat, no two ways about it. Just avoid like a plaque. Now let's see what 820 can do later on.
Everything is a software fix these days, my cat hates me, but wait there is a software fix for that. My dog poops in the house, software fix for that too. My xperia z3+ overheats...software fix for that!