Monitor loses signal, computer becomes unresponsive, and fans spin full speed

For the past few weeks I’ve been having this issue. Sometimes at boot, sometimes randomly during a light load or while sitting idle it will become unresponsive, lose signal to the monitor, all fans spin full speed, the power button does nothing and has to be turned off with the switch on the back. I was able to run benchmarks without issue for several minutes. I do have a pbo setting of +4 all cores because otherwise my cpu won’t boot, but that’s a separate issue.

Things I’ve tried that didn’t help: Reinstalling windows 10 like 6 times on different drives. Updated bios to the latest version. Reseated my ram, gpu, boot drive. Swapped gpu, ram, power supply, boot drive. Removed peripherals. Removed additional drives. Used different ram sticks in different slots. Plugged directly into multiple different wall outlets instead of my ups. Remove cmos battery. Restored bios to default settings. Tried 3 different monitors, one at a time. Ran sfc scannow, chkdsk, dism commands. Disabled windows update on a fresh install.

Booting into windows 7 didn’t seem to have any issues.

Think I’ve narrowed it down to the cpu or motherboard, temps are normal and fans ramp up appropriately under load so I don’t think the aio is going bad though it is 6 years old now. I have thermal paste coming in tomorrow so I can swap out the cpu and motherboard to see if it’s either of them. Any suggestions?

New Pc parts: (old pc parts)

Cpu: Ryzen 5900x(ryzen 1700)

Gpu: RX 6950xt (rx580)

Ram: crucial viper 2x32gb (g.skill trident z 4x8gb)

Psu:corsair hx1000i(thermaltake toughpower 750)

Motherboard: asrock taichi x370(msi b350)

Cooler: fractal design Celsius S36 aio(amd spire wraith)

OS: windows 10