Boot loop

[Coja]

About a month ago my one year old PC started to to reboot with no error displayed under load as if it was overheating. I made sure it was not overheating and updated the drivers but the problem kept getting worse. Now I can barely even get to BIOS let alone Windows.

I have reduced the entire PC to just the PSU, motherboard, CPU and one stick of RAM. Nothing is connected besides these and a CPU fan, not even front I/O, but the problem persists. At most it can idle in BIOS for 20 minutes or I manage to get into windows for about 3 minutes, then it turns off and gets stuck in a reboot loop.

These being:

 

Gigabyte Z170-HD3P

i5-6600k (with Cooler Master hyper 212x)

HyperX Savage 4GB 2133Hz

EVGA Supernova 550 G2 

 

I have tried many things including:

-scanning for malware and removing it

-Windows recovery

-Check Disk shows no error

-Windows Memory Diagnostic shows no error

-sfc scannow shows no error

-updating BIOS (problem persisted on both the previous F4 and the newest F22g version)

-clearing the CMOS

-reseating everything including CPU and its cooler

-tried both RAM sticks in every slot individually

-cooling the southbridge as I noticed it gets much hotter than anything else while idling in BIOS

-visually checked every component and cable but did not find any issue

-checked components for overheating while running

-tested the PSU, power cord and the outlet with a multimeter (good results)

-tried different power outlets

 

I dont know what to do anymore. No suspicious noises or smells. I have never overclocked anything. Voltages for RAM and CPU are correct. Temps sit at 27-30 degree Celsius. The last thing I can think of is getting an internal PC speaker to reveal the culprit, but so far I have difficulties even finding any for sale that ship to my country. Any ideas? Thank you.

 

[Ukaros]

are we talking about a "soft" reboot or basically a crash followed by a reboot?

[Coja]

4 minutes ago, Ukaros said:

are we talking about a "soft" reboot or basically a crash followed by a reboot?

Turns off instantly as if you would pull the plug, waits about a second or so, then attempts to reboot.

[Ukaros]

have u upgraded anything? and what psu do u have?

[Coja]

2 minutes ago, Ukaros said:

have u upgraded anything? and what psu do u have?

There were no hardware changes, no BIOS changes, only updated drivers after the problem showed up.

PSU is EVGA Supernova 550 G2 (550W, 80+ gold rating)

[Ukaros]

8 minutes ago, Coja said:

EVGA Supernova 550 G2 (550W, 80+ gold rating)

fuck me u literally wrote it and i didnt see it

well then what graphicscard do u have? or dont u have one?

and how long did it run as it should before this problem started to occure?

 

[Coja]

5 minutes ago, Ukaros said:

what graphicscard do u have?

Gigabyte GTX 1070 G1 Gaming G8

It only happened if I played some demanding videogame, then I updated drivers but nothing changed. Havent played for about two weeks or so and few days ago when I tried to play something it crashed few minutes into the game. After few restarts it escalated into the current situation.