NZFF

After Software Update 5 or 6, I gradually started getting BSOD's, which would happen at completely random times, but the good time before them was fine. Nothing in particular seemed to trigger them, so I emptied my Community folder and dialed down my settings to mostly medium, which looked pretty terrible. The 'good times' became shorter and shorter, and I dreamt of having CTDs, like other people, rather than BSODs. I tried the MSFS 'Repair' function, which didn't do much, and then the 'Reset' function, which basically was just a dirty reinstall, but those were no good either. At that point, I blamed the serious overclock (to 5GHz), which the shop did for me, and perhaps dusty fans or something causing increased temps.

My only remaining option (short of taking it back to the shop) seemed to be a dreaded BIOS flash, which I don't think I've done before. My system was a little over 2 years old and had an Asus Rog Strix 390-F motherboard and it turns out it's quite easy to update using the company's Ezy Flash 3 software. You just need a USB stick and nerves of steel for a few minutes. CPU is a Core i7 9700K, GPU is GeForce GTX 1080Ti.

Amazingly, it worked without a hitch, and the whole instability problem was solved instantly. The update even overclocked the CPU, to slightly less than it was before, without my asking. MSFS now runs like a dream, at very high frames, and I'm gradually increasing the settings to Ultra. So far, it's responding really well and it's still very smooth, - I can hardly believe it.

Anyway, - the problem wasn't the sim, it was just an ageing BIOS that hadn't kept up with developments in technology. Might help someone...

I like reading endings like yours.

Yes, I've thought about the BIOS, my new system actually nagged me constantly to check for a BIOS update when I got it, but I never bothered. I do think it makes sense as a system ages, though.
With my new system, mainly for MSFS, I have kept everything really clean and standard. I wonder if those with MSFS issues have just tweaked something previously (for another sim, maybe) which doesn't suit MSFS. So far I haven't had any issues.
I'm the same with addon utilities and tweaks. I ask myself 'Rob, do you really need this?' and so far I've always answered 'good question, Rob, I'll pass this time.' So I don't use any addon manager, UI improvements or magic tweaks. Let's see how long I can keep my system clean.