System Keeps crashing, rebooting

Hello!

So I am new to troubleshooting HD etc through TrueNAS.

Motherboard - AsRock Rack X470D4U
Memory - 2 x 8 Gig Crucial NON-ECC
I have 1 x 16 Gig ECC but MB won’t even try to
boot (another story)
HD - 5 x 4 Gig Seagate NAS 5400 RPM Ironwolf
Onboard SATA usage
750 Watt PSU
Ryzen 5 3600 CPU
Onboard Video

It happens at random.... 4 days fine then bam reboots like several times. Then maybe a day. It’s all random.
I’ve had to reinstall/format cause of the destruction it...

System Keeps crashing, rebooting