Random Crash/Reboot Error 41

[DrJones]

My PC is I guess around 2-3 years old now.

Intel i7 5930K
64GB Dominator Platinum DDR4 (Overkill I know)
2x GTX1070's SLI
Corsair AX860i PSU
Custom Water Cooling

So this problem only started occurring in the last week. It happens completely randomly. The computer will turn off like someone pulled the power, then automatically reboot into windows like nothing happened.
The only critical error I get in event viewer is Event ID 41.

I've run a memory test, RAM checks out OK
The CPU clock has been set to Default
Temps are WELL within margins (35-40C idle, maybe 60-70 under extreme load)
The power supply self test checks out fine, and if it was the PSU, I would imagine this happening all the time and perhaps at the same moment each time (i.e. at system startup). (This is happening at completely random times and intervals).
No coil whine or abnormalities with the PSU from what I can tell.

My only guess is that I'm plugged into a UPS (big backup power supply/surge protector). I've used this UPS for the entirety of the PC's life. However, when I check the output voltage readout on the UPS, it reads about 190VA, but sometimes jumps to as high as 250VA for a split second and maybe down to 180VA. So I'm going to try plugging directly into the wall to see if the problem continues. Voltage off the UPS reads 115V input and output

I'll also check for any voltage fluctuations showing in the BIOS and post an update here if there are.

Other than that, I really have no clue what could be causing this. No blue screen, no data log, just the unhelpful Event ID 41.

UPDATE: BIOS voltages check out fine, CPU & Cache Voltage are where they should be, RAM is too. 3V read 3.296, 5V read 5.040, and 12V read 12.000, so those are fine also I take it. There are plenty other voltage readings that I don't understand so I wouldn't be able to evaluate those. But the ones I do recognize all check out.