Yesterday, my PC had a BSoD with the message DPC_WATCHDOG_VIOLATION while doing some heavy duty graphical stuff. I have a 2TB M2 SSD running from a PCIE x4 add-on card, and after rebooting, I went into BIOS and noticed the 2TB SSD was absent. I have a spare 512GB M2 SSD that I use in a USB enclosure, which I slotted into the PCIE card, and it detected as normal in BIOS and Windows.

I proceeded to put the 2TB M2 SSD into one of my mobo's built-in M2 slots normally occupied by a 1TB M2 SSD, and the PC didn't POST. Reverted back to the 1TB M2, still didn't POST. Left it switched off for about half an hour, and the PC managed to spring back to life. It's possibly due to overheating, though I've set my PC to beep if the temps are over the safe limit, so it's probably not the CPU. I've made sure to clean out the dust too. Power-cycling the PC might also have helped, where the PC is unplugged and the power button is held down for about 10 seconds.

As it stands, I've put the 2TB M2 into the USB enclosure, and it's running just fine though not the most convenient option. I put all the HDDs & SSDs through SeaTools' usual short tests, and they all tested just fine. CrystalDisk also says everything's hunky dory.

I suspect either the PCIE add-on card might be iffy (even though the 512GB M2 works on it), or it's the mobo's PCIE slot.