Random restarts, on high load & low load

[DamienJ]

Completely defeated by my PC issue, I'm hoping someone here knows about the issue and is able to tell me what's causing this problem.
Will try to keep it short:

My PC restarts with no BSOD once ever hour or every other hour, sometimes restarting twice in 10 minutes. It can be whilst gaming, or watching Youtube, high load, no load.
Event viewer gives me this message :

A fatal hardware error has occurred.
Reported by component: Processor
Core Error Source: Machine Check Exception
Error Type: Cache Hierarchy Error Processor APIC ID: 5
The details view of this entry contains further information. 

Googling this is such a headache because I can't find anyone with the same exact error. Error led me to believe it was CPU, but after swapping CPU and motherboard with my partners mobo,CPU & RAM and that working fine proves it's something else..

So far I have: -Thoroughly cleaned the PC inside out [Fans, GPU, mobo, case]
-Applied new thermal paste on CPU
-Updated BIOS
-Reset BIOS
-Updated GPU
-Reinstalled windows 11
-Factory reset PC [Twice!]
-Tested power supply [It's A'Ok!]
-Health tested my SSD [It's rated "Good 92%" so guess it's not that either?]

 

Specs:

AMD Ryzen 7 5800X
ASUS TUF Gaming A520-M PLUS MOT
(Bios version:  2806 x64)
RTX 3060Ti

850Watt PSU

HyperX DDR4 2333MHz RAM

Windows 11 64Bit

Nothing is overclocked.

 

[RONOTHAN##]

First off, specs? 

 

That said, it sounds like the only thing you haven't checked is the RAM, which that error sounds like it could relate to. I'd be running a memory stress test to see if that shows any sort of issues (which one is best is very CPU dependent, for most Memtest86 is good enough, though for say 12/13th gen DDR5 you want to use Y-Cruncher VST, and a couple Windows bound ones like TestMem5 can show errors a lot quicker and more reliably than Memtest86 can). 

[DamienJ]

Just now, RONOTHAN## said:

First off, specs? 

 

That said, it sounds like the only thing you haven't checked is the RAM, which that error sounds like it could relate to. I'd be running a memory stress test to see if that shows any sort of issues (which one is best is very CPU dependent, for most Memtest86 is good enough, though for say 12/13th gen DDR5 you want to use Y-Cruncher VST, and a couple Windows bound ones like TestMem5 can show errors a lot quicker and more reliably than Memtest86 can). 

Whoops, updating info right away. (With the system swap with my partner, RAM was swapped too.)