Question PC "power shutdown" a few minutes after windows is up

[xKyon]

Hey,

I got a really weird issue.
I bought my PC 5 month ago and a month ago it started shutting down sometimes after windows is up and I start doing things like open a video on youtube or opening a game.
The shutdown is an immediate "power shutdown", as if you pull out the power cable.
I had "Corsair 750W 80+ Gold TX750M" PSU so I bought "Corsair RM850x" but it still happens.
My GPU is "nvidia rtx 3070ti". I tried disconnecting it and turning on the PC with only the intel integrated but the issue still occurs.

If I turn on the PC and don't do anything until the fans become more quiet, then from that point, it won't shut down anymore.

I'm clueless and doesn't have any idea what could cause this.
Please share your thoughts.
Thanks!

PC spec:
PSU: Corsair 850W 2018 80+ Gold RM850x
CPU: Intel Core i7 11700K 3.6Ghz 16MB Cache s1200
Motherboard: GIGABYTE Z590 GAMING X LGA1200
Ram: Kingston HyperX FURY RGB 2x16GB DDR4 3200MHz CL16
SSD/HDD: Corsair MP400 PCIe NVMe M.2 2280 1TB SSD
GPU: Nvidia RTX 3070ti
OS: Windows 10

 

[Barty1884]

Shutting down outright and not crashing/freezing would at least suggest it's hardware related.
What you're describing at first sounds like a thermal shut-down (ie the temps continue to climb & the hardware shuts down to save itself), but that would be the same whether you let it sit & idle for a while or not.

What are you using as a CPU cooler? Are you monitoring temps at all?

If you boot to BIOS and just move around in there, does he issue happen? The likelihood of software causing an outright loss of power is extremely slim (as in I can't even think of one scenario), but this could at least rule that in/out.

 

[xKyon]

Shutting down outright and not crashing/freezing would at least suggest it's hardware related.
What you're describing at first sounds like a thermal shut-down (ie the temps continue to climb & the hardware shuts down to save itself), but that would be the same whether you let it sit & idle for a while or not.

What are you using as a CPU cooler? Are you monitoring temps at all?

If you boot to BIOS and just move around in there, does he issue happen? The likelihood of software causing an outright loss of power is extremely slim (as in I can't even think of one scenario), but this could at least rule that in/out.

My cooler is "Asus TUF LC 240 RGB Gaming Liquid CPU Cooler "
My case is "Asus TUF Gaming GT501 Mid Tower"

I checked the temperatures with "open hardware monitor" but everything seems okay

I'll try moving around the BIOS and see if it happens

 

[xKyon]

Shutting down outright and not crashing/freezing would at least suggest it's hardware related.
What you're describing at first sounds like a thermal shut-down (ie the temps continue to climb & the hardware shuts down to save itself), but that would be the same whether you let it sit & idle for a while or not.

What are you using as a CPU cooler? Are you monitoring temps at all?

If you boot to BIOS and just move around in there, does he issue happen? The likelihood of software causing an outright loss of power is extremely slim (as in I can't even think of one scenario), but this could at least rule that in/out.

Core Temp displays that 3 cores reach 100 Celsius and then the pc shutdown