I just had my system randomly reboot. What is the best way to diagnose/troubleshoot the reason why? What logs should I look at and what am I looking for?
i5-14500
32gb Ram
1x SSD for boot?
Mirrored SSDs for Apps
6x Toshiba in raid z2 for media storage
Cyberpower UPS with monitoring (30 seconds no power shutdown time)
Start from running Memtest.
Check RAM - temperature and PSU first, as BIOS update available.
Ensure that you are not using incompatible Hw (like Realtek NIC)
I guess I do have a realtek nic, specifically the startech dual port with realtek rtl8111h chipset. Is that what caused it? However I have had this in the system for several months with solid use, and no issue up until now. If it is that big of an issue, what is a good alternative for a single or dual nic? For checking the PSU, what is the recommendation? For RAM I will use memtest86. Temps should be fine as I have a lot of cooling. The reboot happened while I was transfering files into the nas.
Realtek NIC is a real possibility, have seen quite a few similar cases.
Intel, as well as avoiding 2.5 Gbps.
Do you have any recommended brands/models? Especially around the $60 point? Looked on newegg, but found brands I don’t know and mostly 2.5gbps
The Intel I350 chip should be around that price. https://www.amazon.it/10Gtek®-EXPI9301CT-Gigabit-Adattatore-desktop/dp/B07B4RL9QJ
if you dont need the dual port, price drop: i210AT is a good choice, but also i219LM; i219V is consumer but work fine too (all personally tested from various motherboard 
).
As davvo said, im one that experienced the same issue time ago, using a realtek integrated nic… for me that happen on high workload, without any significant error log.
