Weird restarts/Weird behaviour

[CJay9209]

Hey guys,

System specs:
MB - ASUS ROG STRIX X670E-E GAMING WIFI
CPU - AMD Ryzen 9 7950X

RAM - Corsair Dominator Titanium 64GB

GPU - Asus Tuf GeForce RTX 4090

PSU - be Quiet! Power Zone 2 1000W / Corsair RM1000x

Storage - Samsung 990pro 2TB (no secondary)

Cooling - Corsair H150I-LCD

OS - Windows 11 Pro

Triple monitor setup - 1440p Odyssey G6's

 

So I'm not new to building but I'm having some weird issues I can't quite make sense of. System is around 13-14 months old and has been rock solid till this week. I've got it behind a 1500VA 1000w UPS.

Issues:
Recently started just cutting out - like not even BSOD. It's like someone cuts the power and all the rgb/fans/screens goes out then the machine just comes back to life a few seconds later. I immediately assumed power supply issue and switched from my year old RM1000x to a brand new be Quiet 1000w supply. After replacing the power supply, the screens take absolutely forever when booting up to even recognize that there's anything connected to them - like 3-5 minutes sometimes. Occasionally I'll have to manually reset to get anything from it. The GPU was previously provided power by Nvidia's adapter which converts 4x8 pin to the newer PCIE 600w plug, but is now supplied directly by the newer pcie 600w cable from the PSU. I wondered if that had something to do with this. Aaaaaanyway, once it's running and I log into windows, every now and again i still have the random hard resets. Wasn't the power supply (I now assume). I figured it might be the UPS as it's getting on towards 6 years old at this point. Replaced it with a higher spec model. Same issues with new UPS installed. Now i seem to have another issue. Every now and then after a hard reset, the bios is resetting itself and I have to go back in and redo my initial configuration steps (RAM setup - ignore CPU fan speed etc).

I'm ready to tap out on this one and admit defeat. Long story short I have 2 groups of issues ( I think):

1 - Random hard resets which haven't been fixed by a PSU replacement or the UPS replacement accompanied by bios reset.

2 - Flaky monitor recognition on startup (issue appeared after installing the new PSU) - sometimes they show up but sometimes not, and usually only after windows starts to load which seems to take a bit longer than usual. I rarely get to see a bios post screen.

 

I've tried the mentioned PSU swap and UPS switch. I have also re-seated everything just in case and because of the bios issue, I've checked and even replaced the bios battery.

Don't really wanna go down the road of the GPU being the problem but it's still under warranty if something is up. I don't have an easy replacement to switch in just to try although I do have a kinda squirrelly 3090 that I could throw in - solid red lights on all power ports on that card and fans run constantly so I doubt it would be a good test.

I am however leaning into the MB or GPU being the issue.

The restarts seem to be random but it'll run some evening playing anything I throw at it and then other night's it'll just reset a bunch of times when I'm browsing the internet. I don't think it's stress induced.

 

Basically... Halp lol