Question WIN10 Automatically Shut/Reboot Problem

[lottaphotos4]

Ok. Have had this problem for a while now, and it's starting to get annoying.
Going to tag it here in WIN10 because that's what I'm running, and it's where I think the issue is.

The system:
Intel i7-8700K (not overclocking it)
-Corsair HX151 Cooler
Radeon RX Vega
Giant Phantex Case with 5 fans (blowing front to back, bottom to top)

The problem only happens when gaming/high usage.
Mostly playing 7 Days to Die.

In the middle of gaming (GPU temperature between 68 and 72 degrees) system simply SHUTS DOWN (completely, no warning, just "OFF"...then after a 5 second pause, it auto-reboots and acts like everyhthing is fine.

I do not believe this is actual overheating.
I'm inclined to think this is Windows thinking it knows better than me.

I've got the Radeon Adrenaline software running with an aggressive fan curve (really does sound like a jet engine up over 65C).

So, the basic question would be, of course, what the heck is going on?
Yes, it's a heating related issue. No, nothing is showing as hot enough to cause it.

I think it's Windows. I just want to know where, in Windows, I can look for the temperature threshold that is causing the shutdown.
I want to see it, so I at least know what's causing these random shutdowns.

(I do not think it's the PSU: Corsair 750HXI, by my calculations, peak load it's still got 100W of margain.)

Thanks for your time reading all that.
Would really appreciate where in Windows this shutdown is being generated.

 

[Aeacus]

Radeon RX Vega

Which Vega exactly? 56? 64? 64 LC? Frontier Edition?

Since without specifying, it would be as good as i'd say that i have Nvidia GeForce GTX.

I do not think it's the PSU: Corsair 750HXI

How old the PSU is, and was the PSU bought new or used/refurbished?

 

[ubuysa]

By default Windows is configured to auto-restart if a 'system failure' occurs, that's probably what you're seeing. Have a look in C:\Windows\Minidump for any dump files dated at the time of your restarts. If there are any then please zip up all the relevant dumps and upload them (or a link to them) here.

What is the CPU temp at the time of these shutdowns?

Are you running the latest version of your graphics driver?