yes, I tried a clean install and also a downgrade.
I had the Crimson 15.12(.1?) with hotfix installed and now downgraded to 15.7.1 again.
Anyway, the type of the issue changed, as it turned out my method of measuring the temperature was flawed.
It does get stuck in that state because it overheats now, it reaches 100°C and then clocks down to 501MHz.
This is really strange however because it all worked fine up until a few weeks ago. So what I did now was to clean the heatsinks again, which didn't help.
My next step was to change the thermal paste. That didn't help either so I tried that again with only marginal improvements, but still overheats eventually.
I really don't know what happened that it overheats now all of a sudden.
The fans are spinning fine, thermal paste is good, ambient temperatures are as usual(about 20°C)...
The only thing that changed really is the monitor and thus a higher resolution(1920x1080 -> 2560x1440), but I'm under the impression that such a change in screen resolution shouldn't overheat your graphics card.
Is there anything at all I can do? Right now I'm considering to buy a new heatsink from Arctic, but I really would like not to if avoidable.
Anyway, what do I do about this topic now? Edit it?