It turned out to be problems with "overheating", so I installed [Macs Fan Control](http://www.crystalidea.com/macs-fan-control) and set it a bit aggresive, ie linear, and it "solved" it.

I haven't heard back from the support yet though, but there seems to be an issue with the coolant paste to the north bridge. I'll see when I actually have time to turn it in. It goes from ca `40C` to `95C` in mere seconds when the fans are off.

The reason for "overheating" (ie quotation marks) is that it was not under heavy load, but the "CPU System Agent Core"-sensor was showing high values. See this question, http://apple.stackexchange.com/questions/234892/cpu-system-agent-core-tc0e-tc0f-running-very-high, where I in detail go through my temps and sensor data.