Question PC startup issues, there's always the chance of unexpected shutdown ?

[koro5]

I am experiencing problems with the startup of my PC, if I boot it, sometimes it will work like a completely normal PC, but other times, like if I go afk when I turn it on, I come back to it turned off. Sometimes even if I log in right away after a few minutes it will sometimes freeze then shut down, or just completely shut down by itself with no freezes instead. I figured that it is maybe the ram sticks being faulty? Or possibly the power supply? But when it does turn off from startup I cannot turn it back on unless I take out a ram stick and push it back in, then that would get it to turn on. But doing that still has the possibility of having the problem of the startup not working again or get passed the log in screen but freeze and or turn off again.

Sometimes it will just work like a charm. But I honestly have no clue what would be causing it to do that, but I would like to try to get this fixed and not buy the wrong thing to try and fix something that isn't broken if it isn't hardware related. I even downgraded my Windows 11 to Windows 10 to see if that fixed anything Windows-related that was causing any issues, but every clean/reset of the PC, it keeps happening, which makes me think it is unfortunately a hardware issue.

All of my hardware drivers are updated to the latest as well, and if it does work fine for the couple of minutes that it's on without turning off I am able to keep it on for days, which I have been doing to avoid the issue. I find it weird that it's doing that on startup but not when it's on for days at a time, if that's anything of note to help. If anyone could help me with my issue, it would greatly be appreciated! Thanks in advance.

My specs:
CPU: i5-12400F
GPU: NVIDIA GeForce RTX 4070 Super
Motherboard:
ASUS ROG Maximus Z690 Hero [Evangelion Edition]
CORSAIR VENGEANCE RGB
[4800MHz] [2 x 16GB] [DDR5]
SSDs:
Samsung 990 PRO
WD Blue SN570
PSU:
NZXT S650
Case:
NZXT H9 Flow
CPU Cooler: DEEPCOOL GAMMAXX GTE V2
Operating System: Microsoft Windows 10 Pro
Fans:
x6 Lian-Li SL-Infinity Fans 120mm
x1 NZXT stock fan 120mm

 

[Lutfij]

Welcome to the forums, newcomer!

Or possibly the power supply?
If you have a hunch that it's the PSU, you should source(borrow, not but) a reliably built PSU with slightly more power than your entire system needs then test it out. If the issue is averted, then it's your PSU all along.

PSU: NZXT S650
That unit's a rebadged Seasonic PSU.

I even downgraded my windows 11 to windows 10 to see if that fixed anything windows/software sided that was causing any issues, but every clean/reset of the PC, it keeps happening,
Where did you source the installer for your OS?

Motherboard: ASUS ROG Maximus Z690 Hero [Evangelion Edition]
BIOS version for your motherboard?

CORSAIR VENGEANCE RGB [4800MHz] [2 x 16GB] [DDR5]
Got a link to this ram kit? You should've bought a dual channel ram kit with at least 6000MHz on the frequency, alongside tight timings.