Optane is at $5k for a 1.5 TB drive while the OP quotes $18k for 1.5 TB of RAM. https://www.intel.com/content/www/us/en/products/memory-storage/solid-state-driv

Optane is at $5k for a 1.5 TB drive while the OP quotes $18k for 1.5 TB of RAM. https://www.intel.com/content/www/us/en/products/memory-storage/solid-state-drives/data-center-ssds/optane-dc-ssd-series/optane-dc-p4800x-series.html https://www.intel.com/content/www/us/en/products/memory-stor... Being able to reach 12 TB+ with something like Optane is much more likely than with RDIMMs though, and memory latencies would probably get insane enough that Optane would start looking viable anyway.