[SOLVED] Pulsating framerate

[ThijmenB]

I have a Powercolor Red Devil RX 480 8 GB. Ever since some 2017 drivers I've had problems with pulsating framerate. About a year ago I installed the newest drivers and everything seemed to work, so I started gaming again. I have put a lot of hours into Assassin's Creed Odyssey lately and been having a good stable framerate on high settings. After completing all main quests, I went to play The Witcher 3 again, I stopped because the game was unbearable with the pulsating framerate. But then I noticed that this game still had the problem. So I started furmark and that really showed the problem good. Underclocking the GPU does make it better but no matter how much I lower the clockspeed, the problem is still there. When the GPU is cold the framerate is good, but after it warms up (about 5 seconds of heavy load) the problem occurs. Does anyone have any idea what the problem may be? Is the GPU dead, or is it the PSU?
Temperatures are all below 70C.
I have already tried reinstalling the drivers.
My specs:
Motherboard: MSI Z170-A Pro.
CPU: Intel i5-6600K
GPU: Powercolor Red Devil RX 480 8 GB
PSU: Cooler Master GM G650M
RAM: 2x 8 GB Crucial CT8G4DFD8213
Here is a video showing the problem:

View: https://www.youtube.com/watch?v=FyIDz-ao7oE

 

[kerberos_20]

hey, thats called stuttering, but really whats with those 5sec videos
anway run latency mon, to see if its driver related
https://www.resplendence.com/latencymon
open it and hit green play button, leave it in background
play that witcher or furmark for few minutes
then report back if it catches anything

 

[ThijmenB]

So I visited a friend today and we managed to fix it. I've had this problem for 4 years and the fix was so easy. We took the heat sink off. We cleaned the old thermal paste off. The heat pad on the VRMs came off so we put it back (it had indents of all the electronics). We put it together and the problem was fixed. It really was that easy.