Installed an Arctic Accelero on my GPU, now temp jumps massively as soon as I start a game and screen goes black

[Tvei]

The stock fan on my Sapphire R7 260X stopped working properly so I bought this ARCTIC Accelero L2 PLUS as a cheap replacement.

Now I just installed it and normal browsing and such seems to work fine, but when I test-run Wasteland 2 the temperature increases by 20-30°C within seconds (almost instantly) and the screen goes black and "signal is lost" message appears on the screen and there's a buzzing sound. (The PC doesn't shut down though, it keeps "running" and I have to shut it down and restart manually.)

Could the thermal paste be the issue? It was pre-applied but I had to re-arrange the heatsink once during installation, maybe that caused issues?

 

[Aizazst]

Yes, it's recommended to re-apply thermal paste whenever the heat sink is removed (When the thermal paste is old). Moreover ensure good contact between the processor and Heatsink.