Well at least I can say I have no issues on the 3800X even if I have tortured it with excessive voltage since day one.
100% stable on stock on Gigabyte X570 Aorus Xtreme F12f. Took the occasion as I updated my BIOS from F12a to F12f version.
Just loaded optimized defaults and it was all OK, even went and enabled XMP @ 4000Mhz and all was well as I only needed increase stock DRAM voltage from 1.200 -> 1.350V for it to work there.
So I wonder what the issue is with the higher core counts. I've used "excessive" voltage on my 3800X a long time and as far as I can tell it's not changed a bit since start.
Gigabyte X570 AORUS XTREME, Ryzen 7 3800X PBO boost, 2x8GB 4866/1900 126.96.36.199.90.tRFC 680 1T 1.650V [Micron Rev.J]
4x8GB 3800/1900 188.8.131.52.66.tRFC 600 1T 1.700V Kingston HX434C19FB2K2/16 3466C19 1.2V (Micron Rev.E 19nm [D9VPP]),
2x8GB Kingston HX436C17FB3K2/16 3600C17 1.35V (Micron Rev.J 17nm),
2x8GB 3866/1933 184.108.40.206.60.tRFC 448 1T 1.590V Kingston HX436C17FB3K2/16 3600C17 1.35V (Hynix DJR 17nm)