In the stress test, just one core reached 100 degrees.
In the stress test, just one core reached 100 degrees.
As others pointed out, it might be an unusual connection. Gradually secure your fasteners in an X shape, repeating a few times and ensuring each corner isn’t fully tightened during the initial run.
Well, the 8th generation Intel still relied on toothpaste. It might mean your TIM is not great. Delidding could be beneficial, assuming the rest of things hold up as you say.
It's essentially a situation where you can't turn back. If you open it up, you'll need to swap the TIM anyway.
I managed it on my 8700k with little effort, thanks to the rockit kit. It made a big difference, though unless you're pushing it hard, I'm not sure it's necessary. If it's just stock performance, I think the TIM isn't to blame for the heat. You might not be adjusting the cooler enough.
It worked well before the aftermarket cooler... Now it's acting differently...
Did you confirm the film was taken off from the base of the new cooler? It might be a defective unit with an uneven coldplate. I recommend removing all old paste from the CPU and cooler, swapping it with fresh paste and securing everything properly according to the instructions. Use the right mounting hardware for your socket.