I use HWinfo
It reads before it crashes the game 80C-
85C i think
When the game crash, Does Windows crash too and you have to restart the PC?
Im asking cause if you start HWiNFO Sensors Only, then start the Game and go play, and after 3 hours game crash (but only the game), HWiNFO should have the MAX temp reading value saved on the MAX column. So is not hard to see if its 80°C, 85°C or something else.
And while you use HWinfo, Whats the temp reading of the GPU after the game crash?, GPU is down there if you scroll down with your mouse.
Perhaps both CPU and GPu gets too hot cause you may not have good airflow on your case?
Also as veolictyg4 explained PB (Presicion Bost PB), which is like Intel's Turbo Boost, will boost your Ryzen CPU so it can reach 4.2GHz on 1 core and probably around 4.0GHz on all cores loads. Thats a standard behavior for Ryzen, like it is a for Intel CPUs with Turbo Boost.
Ryzen 2600X has a base clock of 3600MHz and 1 core boost speed of 4.2Ghz (
https://www.amd.com/en/products/cpu/amd-ryzen-5-2600x). You can disable PB if you don't like it. Just like velocityg4 wrote.
Cheers