CMS 8GB (2X4GB) DDR3 10600 1333MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z400 Workstation for Server Only - B80
HP Z400 almost 48GB ram Upgrade + RamDisk Benchmarks - YouTube
Amazon.com: A-Tech 4GB for HP HP Z400 Workstation (6 DIMM Slots) (1 x 4GB) PC3-12800 (DDR3-1600) ECC Unbuffered UDIMM 240-Pin 1Rx8 1.35V Server Memory RAM : Electronics
12GB KIT (6 x 2GB) for HP-Compaq Z Workstation Series Z400 (6 DIMM Slots). DIMM DDR3 ECC Unbuffered PC3-10600E 1333MHz Server Ram Memory. Genuine A-Tech Brand. at Amazon.com
Solved: Z400 RAM - Page 2 - HP Support Community - 6148900
8GB 2X4GB RAM Memory for Compaq HP Z Series Workstations Z400 Workstation (6 DIMM Slots) Black Diamond Memory Module 240pin PC3-10600 1333MHz DDR3 ECC UDIMM Upgrade - Walmart.com
Solved: Z400 RAM - Page 2 - HP Support Community - 6148900
HP Z400 Workstation - Memory | HP® Customer Support