Question System experiencing intermittent power loss / reboots (error 41) even after replacing PSU and motherboard

Oct 25, 2020
About a month ago, I built a new computer (specs below), buying new parts for everything but re-using my existing video card. After setting it up, this computer worked perfectly fine for about two weeks, at which point it started intermittently losing power and restarting. After reboot, the windows event log would show Error 41 with an error code value of zero, seemingly indicating that the system did, in fact, lose power. The timing of the reboots mostly seemed to be random, not during particular tasks. OpenHardware monitor did not show any components with high temperatures.

At this point, I:
  • Reinstalled windows from scratch. This did not help, and in fact I am not able to complete the installation due to the power losses.
  • Flashed the BIOS with a new version.
  • Replaced the PSU with a new version of the same PSU (specs below)
  • Replaced the Motherboard with a new, different motherboard.
  • Test the system on a different outlet/breaker with a different surge protector.
None of these seem affect the problem at all.

As a sanity check, I put my only video card back into my OLD system, and was able to install windows successfully on the first try, which is a real contrast with my new system, which has failed to install windows probably twenty or thirty times without success now. HOWEVER, the old system has gotten two Error 41s since reinstalling windows yesterday! As far as I know, the only commonalities between the old system and new are the video card and the electrical system in my house. Prior to building the new system, the old system did not have these issues.

I also performed a long list of other component changes/checks (see below), that are a lot less likely to be related to the problem, and none of these changes help either.

I'm wondering if anyone here can make sense of this, and recommend me some next steps? Some options I have thought about:
  1. Replace the CPU in the new system, as it seems to be the only component (besides the video card), that hasn't been replaced or ruled out in the new system. But, this doesn't explain the similar (but less frequent?) issues. (And I don't think this is the symptom of a CPU issue?)
  2. Get a UPS (or otherwise investigate power stability more). But, the old system doesn't encounter issues at nearly the same frequency as the new system does. And, the restarts aren't quite random -- e.g. they don't happen in the bios, they seem more likely to happen during certain steps of the windows installation.
  3. Replace the video card -- it's the only common component between the two systems. But, the symptoms really don't seem to be the symptoms of a faulty video card. And, the video card worked fine previously in the old system.
  4. Investigate the PSU more. But, the issue occurred with two different PSUs, and it seems very unlikely they both have the same problem.
System Specs (for the new system):
CPU: AMD Ryzen 5 3600X 3.8 GHz 6-Core Processor ($234.99 @ B&H)
Motherboard: Gigabyte B550 AORUS PRO AC ATX AM4 Motherboard ($179.00 @ Amazon)
Second Motherboard: MSI MPG B550 GAMING CARBON WIFI AM4 AMD B550
Memory: G.Skill Ripjaws V Series 32 GB (2 x 16 GB) DDR4-3200 CL16 Memory ($109.99 @ Newegg)
Storage: Western Digital Blue 1 TB M.2-2280 Solid State Drive ($104.99 @ Newegg)
Video Card: MSI GeForce GTX 970 4 GB Twin Frozr V Video Card (the existing, old video card)
Case: NZXT H510 ATX Mid Tower Case ($69.98 @ Amazon)
Power Supply: Corsair RM (2019) 750 W 80+ Gold Certified Fully Modular ATX Power Supply ($124.99 @ Corsair)

Other, more minor tests I've run, all with no effect:
  • Run with only one stick of ram (trying twice, once with each ram stick I have)
  • Disable Precision Boost Overdrive (Auto -> Disabled) in BIOS
  • Try different DRAM BIOS settings
  • Tested with different OS drive, removing all other HDDRs
  • Removed as many optional motherboard connectors and peripherals as possible
  • Swap out power cable and HDMI cable.