Question System powers off by itself. Bad mobo?


Dec 21, 2016
My system has now started to power off from time to time. Just an instant, hard loss of power - no shut down, as far as I can tell.

It's happened while I've been using it, playing a game, after some indeterminate period of time. However, twice it's happened when I unplugged a USB device (I think both times it was my 2FA token).

The trouble seemed to start up after installing a new hard disk, but it hasn't gone away after removing that hard disk.

I grabbed a system monitoring app and logged the hardware sensor data on a one second interval, used the system till the problem happened again, then booted it back up and sent the data somewhere else so I could look at it. Absolutely nothing unusual happened, that I can see, in the leadup to the data cutting off. I had thought it might be overheating, but the temperature data is absolutely fine.

I recently had two drives die out of the blue (post here), and as a result I replaced the PSU with a brand new 650W Corsair.

Given that it's not overheating, it's not the PSU, it can apparently be provoked via USB (while also happening randomly), and given I had this other problem of drives dying, that just leaves the motherboard as the only possible culprit, right? It's almost exactly three years old, a Gigabyte GA-B150M-D3H. Time to replace it?

System specs follow, including purchase dates since my system is a mix of different parts purchased and installed at different times.
Motherboard: Gigabyte B150M-D3H (15/12/2016).
PSU: Corsair CX 650 (23/12/2019).
CPU: Intel Core i5 6600K (15/12/2016 ).
RAM: Kingston HyperX Fury 16GB (2x8GB) 2133MHz DDR4 (15/12/2016).
Graphics: Zotac GeForce GTX 1070 (26/12/2017).
  • 1 TB HDD ??? (??? old. years and years ago).
  • 500 GB Samsung 970 EVO Plus NVME (18/12/2019).
  • 2 TB HDD ??? (second hand, installed ~20//01/2020, removed ~22/01/2020).
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