Odd Ryzen Tempurature?

[SplinterzMC]

I have an extremely obscure question regarding my R7 1800x.

 

I'm currently running my 1800x on an Asus Crosshair Hero with a Noctua NH D15s and since the latest Asus bios update I was able to get a comfortable overclock of 4 Ghtz @ 1.375v which stayed stable through my stress tests and formthe better part of a week. Today I had a general CPU failure, black screen and mobo debugger flashing 8. I went back through the bios and clicked it back to 3.6 and ran some more stress tests. Voltages were perfect ?@1.375  and temps never went above 68c. However it was when I turned off the tests that I saw something very strange. At idle the 1800 was jumping erratically from 42 back up past 50 (I have a vid but it's over 20 mb). Past installing my cooler wrong (which I doubt as I had a stable 68c at full load after 30 minutes)  I have no idea what could cause such a dramatic fluctuation, I'm comvinced whatever is causing this is also the cause for my CPU failure today. Can't find much on the interwebs about temperature fluctuation past the 20c offset on the 1700x and 1800x. Thoughts?

[SplinterzMC]

Please forgive my terrible grammar/spelling, I'm typing this from my mobile.

[Olly1923]

How are you reading the temp, could it possibly just be the software that is reading this temp?

[SplinterzMC]

I was using HWmonitor, their most recent patch included Ryzen CPU support.

[Brooksie359]

I've seen the same sort of thing happen on my r7 1700 but it never caused a crash. There is likely a different cause. As for the buggy thermal readings I'm probably going to assume it is just a software thing as the thermal couples don't give a thermal reading but rather an analog signal that needs to be used to calculate temperature and this might be what is causing the weird temp reports.

[SplinterzMC]

Hmmm back to the drawing board regarding the crash then. Ah I did not know that about the temp readings that's interesting stuff, also I guess it is the first revision of the HWMonitor support for ryzen so you are probably right.