Okay so still crashing. DRAM voltage was 1.38v. Still crashed. UEFI boot screen spinny wheel even got corrupted and it froze on that. BIOS reset itself, 2nd time that's happened. Kept mostly default except enabled SVM and quiet mode, no XMP profile and it crashed today except this time with usbxhci.sys driver_irql_not_less_or_equal. So now I'm thinking the motherboard is faulty, or drivers not quite stable on Windows 11 yet? Guess I'll wait until it's released and hopefully by then if this is a hardware fault it's become more consistent so troubleshooting will be easier.