I am actually experiencing very similar issue. Unraid server on AMD platform with 32GB RAM. I was using XMP profile as of the RAM specifications and all was fine for about 2 years, but recently, I was getting btrfs issues, ran memtest86 and - got lots of errors. Swapped the RAM with my Windows PC (also AMD, but different board/cpu ) and it confirmed the above, RAM from Unraid failed on different PC as well, but RAM form that PC was fine in Unraid.
I am currently in RMA process (lifetime warranty), Unraid is running on 16GB 3200 MHz from reserve. Also "memtested", and all good. Running on XMP profile, as memtest did not report any errors on this speed.
Wondering why it happened after about 2 years without any issues, I was even running VMs, so the RAM was about 80% used at times. To date, I had only RAM which either did not work from day 1 or did and then it did all the time.
