There can be many reasons why your CPU might have sudden temperature spikes and dips. This will explain the reasons, and then share how you can fix it: Mind you, the BIOS/UEFI settings for each PC ...
The downside is that the program does cost $29.99, but you can often find it available on sale for $10. As I noted above, TG ...
Personally, I find HWiNFO to be the best option ... and it's also good for checking stability. How to check your CPU temperature using Ryzen Master or Intel XTU If you have already overclocked ...