PC behaves erratically following each cold or initial power-on, with network failure and intense CPU heat.
PC behaves erratically following each cold or initial power-on, with network failure and intense CPU heat.
Hello, I recently assembled a PC for my friend with these specifications: CPU – AMD Ryzen 7 9700X, Motherboard – Gigabyte B650 Gaming X AX V2 (BIOS v36), GPU – Gigabyte Windforce RTX 5070, 12GB RAM – Kingston Fury Beast DDR5 RGB 6000MHz CL30 (2x16GB), Cooler – Cooler Master MasterLiquid 240 Core ARGB, PSU – Cooler Master MWE Gold 750 V2 ATX 3.1, Storage – Kingston NV3 M.2 NVMe 2TB, Case – NZXT H2 Flow RGB, OS – Windows 11 Pro x64 (fully updated), Network – initially working but failed after first boot).
At first, everything appeared normal during gaming tests (Clair Obscur). However, after restarting the PC and plugging it back in the next day, the motherboard stopped recognizing the LAN cable completely. I’ve tried several fixes: installed the newest LAN driver, updated all system software from Gigabyte’s site, adjusted BIOS settings (disabling Fast Boot, Network Stack, ERP Ready, restoring AC power loss), cleared CMOS, reset network preferences multiple times, turned off fast startup in Windows Power Options, and even temporarily cut power to the power strip for a few seconds.
The odd thing is that turning off the power strip briefly and then restoring power restored LAN functionality. It seems the motherboard sometimes fails to initialize after a cold boot with power still connected, but switching off the PSU for 5 seconds resolves the problem. During idle, CPU temperatures remain high (90°C+), causing freezing or extreme slowness despite near-zero usage. In BIOS, CPU temps are normal (39–44°C) right after startup.
Occasionally, a single reset fixes the issue, sometimes it takes 3–5 attempts or waiting 5 minutes post-boot. Once stable, the PC runs smoothly for over ten hours under heavy load with perfect temperatures and no crashes. The problem only occurs during initial booting, never while operating.
I’ve already tried reseating CPU and RAM without success, checked cooler mount and paste application, verified pump and fan connections, but nothing changed. I’m confident in my build process, though I’m seeking advice or suggestions to resolve these persistent issues.
Thank you for the feedback. I plan to test it, though I think it wouldn't clarify a dead LAN during startup. The diodes on the motherboard near the LAN port seem to be faulty even before the operating system launches. After resetting, they light up again when the LAN is supposed to function properly.