Question Bizarre Crashing — Out of Ideas

Sep 24, 2021
Howdy, all!

I feel incredibly lame being That Guy who isn't a forum regular, yet will drop in to ask for help. But I've been trying to resolve an issue for three weeks now, and I've just hit a dead end. Anybody who digs a puzzler, I think I might have one.

I recently got back into PC gaming after about a decade off, so I'm generally conversant in the broad strokes while catching up on what's changed over the past decade. Anyway, here's the build in question:

Asus ROG Maximus XI Hero Wi-Fi
Intel Core i9-9900KS 4 Ghz 8-Core
EVGA GeForce RTX 3080 Ti FTW3 Ultra
G.Skill Trident Z RGB 32Gb (4x8)
WD SN750 2Tb M.2-2280 NVME SSD
Corsair AXi 1600w W 80+
Samsung Odyssey G9

The issues started when installing the current GPU. I was previously using a ROG Strix 2080Ti, and it ran silky smooth like that for two years.

On first install of the new GPU, I started getting a 97 post code on the mobo, and I'd have to reset the CMOS anytime I restarted the computer to get it to boot. Updating the BIOS seemed to cure that one.

Second issue at the same time was a really bizarre one... fast user switching died on me. Anytime I tried to switch users, the monitor would go black and I'd have to do a hard shutdown. This was never resolved, but my attempt to fix this issue is when things really went sideways.

I tried doing a simple reinstall of Windows 10 (Home) right over the top of the current install. After doing that and getting everything reinstalled and looking pretty again, the thing started crashing. A lot. Mostly while trying to play Battletech, but enough in other games and even while idling on the desktop to make it clear that Battletech wasn't the issue. Crashes are usually a total screen freeze and it becomes non-responsive, but sometimes there is audio stuttering and sometimes I get a BSOD noting a watchdog violation.

Eh, maybe installing Windows 10 over the top of the old install wasn't the greatest idea. No problem, I'll just do a clean install.

That was about two weeks ago. Since then, I've tried the following:

  • Clean reinstall of Win10 including completely departitioning and nuking the SSD.
  • Updated everything to latest and greatest drivers.
  • Rolled all drivers back to about a year ago.
  • Updated BIOS.
  • Rolled BIOS back to about a year ago.
  • Updated VBIOS.
  • Rolled back VBIOS to factory default.
  • SSD diagnostic.
  • RAM diagnostic.
  • Swapped stock DP cable for new reputable one.
  • RMAed video card and got a brand spanking new one.
After every change, same issue.

On my last attempt, after installing the shiny new replacement video card, I did a complete nuke and reinstall of Win10. Updated to latest Nvidia driver, installed Steam, launched Battletech. That's it. Nothing else. Crashed within 3 minutes.

The only other things I can think of are mobo or PSU failure, but from my admittedly limited knowledge it doesn't sound like a PSU issue. And a mobo failure that just happens to coincide with the installation of the new video card seems... unlikely?

Any thoughts would be greatly appreciated. I'm out of ideas.

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