Computer Problems, Again (Patreon)

So, hey, posted this on Tom's Hardware. Figured you might want to know as well:

My desktop started restarting occasionally, randomly. Within a day, it was at a point where it wouldn't even boot all the way. I replaced the power supply, and it was able to boot to Windows every time. Cool. 

Problem was, the motherboard was no longer detecting my USB keyboard, but it was still under Warranty, so I replaced the motherboard (ASRock X99 Extreme4 with the latest BIOS). I reinstalled it today. Great! Everything is working perfectly--except for one hiccup: the motherboard sees all four of my RAM sticks in the UEFI system checker, plugged into the four correct slots, but on the front page, it says it's in Dual-channel mode, and it only shows 8GB of the 16GB of RAM (they came in a kit, meant to be used together), in slots A1 and C1.

And while I was trying to figure out what was going on, it started restarting on me again.

...in fact, I just heard it restart in the other room. Wasn't even logged into Windows. Booted it up to the login screen. Five minutes later, boom, restart.

...and there it goes again, a few seconds later.

Since that post, I have checked all four sticks of RAM individually, again, just to be sure. Still restarting.

My gut tells me the restarts and the RAM channels are unrelated. I mean, I guess it's possible that ASRock sent me a SECOND bad motherboard? I don't know. But it's frustrating. I want to get this video up and my desktop continues to exhibit problems I have no idea how to solve.