The ECC memory has been stable for 24 hours. That’s a good sign, but I’m not going to count my chickens just yet. Most interesting aspect of this is that the RAM is running at 2666, rather than 3200, so now I’m curious how the non-ECC modules perform at slower speeds.
I’m working on another Ryzen 9 3900X server running Proxmox. This one’s running 64GB of non-ECC DDR4-2400, and I know it’s been stable in other situations using multiple other Linux distributions. Needs a bit more storage, though.