Sadly 128GB is easy without ECC, but hard with ECC. There are 16GB ubuffered ECC dimms around for $100 or so, but no 32GB ECC I could find. So 64GB ECC is eas

Sadly 128GB is easy without ECC, but hard with ECC. There are 16GB ubuffered ECC dimms around for $100 or so, but no 32GB ECC I could find. So 64GB ECC is easy, 128GB ECC not ... unless you upgrade to one of the "P" Epycs like the 7302P or 7402P. That gets you 16 cores/32 threads (ryzen 3900 x = 12 cores/24 threads) but also 4 times the memory bandwidth.