Z390 AORUS ULTRA - system randomly restarts itself

[HunkUmbrella]

 PC just restart itself on critical error (in event log) without any bluescreen or else, and just restarts, but the strange thing is that it don't happen when PC is on stress load, benchmarking or gaming, but it always happens on low load - as working process in Photoshop or just serfing web in browser, or just system was idle for some hours.
I tried update the drivers, I updated my Bios (updates of Bios didn't helped, last update just make it reset bios settings after crash), I tested RAM, I dont know what is the problem causing it.
Attaching event_config files, if the size is too big, then providing google drive url:
https://drive.google.com/file/d/1lb0QNFzmyb7zUc4oNe-IGCTuo1Fo9cxf/view?usp=sharing

[shadowsports]

Greetings,
Instead of having us sift through the event logs,... just tell us what the error is? 

[dmdilks]

It might be a windows update problem.

https://www.techradar.com/news/disastrous-windows-10-update-is-breaking-some-pcs

[HunkUmbrella]

Greetings,
Instead of having us sift through the event logs,... just tell us what the error is? 

Sry missed the notification about reply.
It is - Critical Error, Event ID 43 - Kernel - Power
The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.

And this dont explain anything, that's why I pinned logs here, as I said before it just dont happens when system is on stress test except only 1 - XTU  (Intel extreme tuning utility) The crash happens if testing the system with benchmark type 1, but wont crash on benchmark type 2

[HunkUmbrella]

It might be a windows update problem.

https://www.techradar.com/news/disastrous-windows-10-update-is-breaking-some-pcs

I am not sure its about it, cause it started to happen even before those updates took place.
I thought on PSU first, but PSU test runs smoothly on test software at least, I checked the load, it even wont come close to PSU limits.  I will still try to test using different PSU.