The ideal ratio of cores to memory channels /bandwidth “sweet-spot” (i.e. not bottle-necking the cores with inadequate memory access) varies markedly with the work you are performing. If you are planning on using the system for software development especially for very large builds (like myself when I built my Thread Ripper Pro 64-cores system) then the recommendations I found (and which worked well for me) were:
- for 32 cores, 4 channels of memory (i.e. Thread Ripper)
- for 64 cores, 8 channels of memory (i.e. Thread Ripper Pro).
- If you are going higher than 64 cores, then you may want the 12 channels available on the current generation of Epyc processors.