Question PC randomly turns off and back on immediately. (Temps fine, no dust buildup)

[parama3500]

Around a month ago, suddenly my PC would freeze, that I cant do anything other than turn it off physically. This happened both when PC was idle or under load. However, this issue automatically resolved.

Then now, I'm having a new issue. Also happens both when idle and under load, also when booting or at BIOS. PC would randomly turn off as if the power went off and restarts back just after a second or two after turning off. This really pisses me off, as it happens multiple times a day.
As said, temps are fine and theres no dust buildup. In fact I reassembled the whole PC but the issue retains.

My specs:
i3 4350T with stock cooler
Asus ROG Strix GTX 1660 Ti
Hynix 4GB PC3-12800 DDR3 1600MHZ
Asrock H81M DGS R2.0
Corsair CX650M
Samsung EVO 860 500GB SSD
1TB HDD + 320GB HDD
in the Corsair 460X RGB case
(no part has been overclocked)

Only my CPU, RAM and Mobo are old, other parts are just around 6 months old. Also because I had a freezing issue initially I suspected the RAM. Changing slots didn't work but when I underclocked it and ran at 1067 MHz the PC worked without an issue for around 3 days and then the the issue retained even at 1067 MHz.

I have no way of checking the RAM indpendently, but when I tried memtest, it did 2 passes for 0 errors at its best without restarting and hence I can't do a proper memtest.

 

[Phaaze88]

Reboots regardless of the type of load? Does it still happen with the gpu removed?

If it still happens even after removing the gpu, I'd suggest reinstalling the OS.

 

[parama3500]

Reboots regardless of the type of load? Does it still happen with the gpu removed?

If it still happens even after removing the gpu, I'd suggest reinstalling the OS.

Its not a software issue, the issue persists in BIOS or even when I boot from a USB (even when hard drives are removed)

Ive not tried removing the GPU yet, would try and update.

 

[rgd1101]

Test with a different psu

 

[shinmarwan]

I have the exact same problem I suspect the psu

 

[parama3500]

I have the exact same problem I suspect the psu

Yeah can be it, but this is my first time buying an expensive psu, been using potato psu so long and had 0 issues. Anyway, I tried removing the CMOS battery and so far, the random restart frequency had dropped to once a day. Not really sure tho if it was the solution

 

[herveRed]

Hi, i have the same problem, it's not GPU, CPU... not hot. i had some start up freeze that i could fix after moving my 4 ddr3 4go... the pc restart with World of warcraft, some time with supreme commander, it does not with starcraft 2 or gta5... so i am getting new ram tomorrow, will see... of course, it's not the ssd or hard drive, it s not the system because it did on windows 7 and on this new win10... dram may be a [language]