I have kept a watch on the temperature under load. Highest temp is at around 71 celsius.
I try to keep as much programs closed as possible when I play something, although the AMD Gaming Evolved App is running and maybe something like Garena when I play LoL.
Sometimes the crash looks like this (these are not my videos btw) http://www.youtube.com/watch?feature=player_detailpage&v=OSu1z9BVeLY
And some other time it looks like this http://www.youtube.com/watch?v=owEun8k8g48
It's pretty random, it can happen anytime and the only thing I can do is resetting the PC.
Also sometimes there can be a looping sound, a bit like a buzzing sound but it's from the speaker.