A few words about memory:
The RAM, which was on the mobo QVL, is rated for 6400. I enabled the XMP profile, which auto set it to 6400. When I first built the machine I ran a variety of memory tests, stability tests, PRIME95, OCCT, and so on. Everything was stable, ran fine, etc. I've used the machine for almost a full year in some demanding situations with tons of apps loaded, all cpu loads, a AAA title or two. Zero blue screens for the year.
When I blue screened the first time a month or so ago, I ran a memtest, and at 6400, the test failed immediately. So something has changed. I moved it to 5800 and re-ran my tests, multiple times. Passed just fine.
This message on gigabyte's site is not lost on me:
* When running EXPO/XMP at DDR5-5200 or higher, the system's stability may vary by AMD processor and memory module's margin of capabilities.
and I mostly get it -- YMMV if you're running faster. But I think I did a pretty good job of establishing that the configuration was stable.....
I set the memory to the JEDEC default of 4800.... rebooted..... and blue screened within the first 10 minutes.
G.SKILL support is offering a return under warranty. But I don't want to go swapping out hardware if this is a driver/windows/software problem.