“Why haven’t we seen EPYC+HBM sooner? EPYC has been focused on high volume markets, which is why you don’t see EPYC with more than 2 sockets,” Park posted on Bluesky. “You can’t swap out your DDR5 controllers and add HBM controllers/stacks and call it a day. HBM forces certain design choices (e.g., every HBM3 stack requires sixteen 64-bit channels).
“Flexibility: with HBM, you can’t upgrade capacity or have lower cost versions with fewer channels populated," he added. "Generally, CPUs don’t require that much bandwidth.”
Sounds like HBM equipped CPUs are a rather niche and specific use case. Surprised that it's not clear whether this CPU has regular Zen 4 or Zen 4c cores.