HP 805351-B21 32GB (1x32GB) SDRAM DIMM - TechnoDeals USA
HP 32GB (1 x 32GB) PC4-2400 (DDR4-2400) Server Memory (809083-091) for sale online | eBay
HP 805351-B21 32GB (1x32GB) DDR4 2400 (PC4 19200) ECC Registered RDIMM Memory by NEMIX RAM Server Memory - Newegg.com
Adamanta Micron Original 32GB (1x32GB) Server Memory Upgrade for HP Z640 Workstation Single and Dual CPU DDR4 2400MHZ PC4-19200 ECC Registered Chip 2Rx4 CL17 1.2v RAM at Amazon.com