Why is the CPU temperature jumping?

Question

Iron

CPU: FX 8320
Mother: 970A-DS3P
PSU: Cooler Master G750M
Recently I completely cleaned my computer and ran into this problem:
I noticed that the CPU cooler began to howl. I checked the temperature through the program (AIDA64) and the turn of the bios. And here and there the temperature in idle time jumps from 25 to 75 (!) degrees. And it's idle! At the same time, the vidyukha and the motherboard almost do not heat up. The northbridge heats up to 85.
I used to howl too, but the temperature did not rise above 30 in idle time.
I already changed the thermal paste, and removed the overclocking, and checked the coolers (I thought the MB was blowing in the wrong direction).
What could be the problem? Why does the temperature jump so much and generally heats up in principle?
Thank you.

Answer 1

Is he really warm? Put your hand in when the temperature rises from the sensors - is it warm there or not? Processor under load? If yes, check with an antivirus, you never know, the miner has started.