CMS 12GB (3X4GB) DDR3 10600 1333MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z200, Z210, Z400, Z600, Z800 for Server Only - B81 at Amazon.com
4GB 2X2GB RAM Memory for Compaq HP Z Series Workstations Z200 Workstation, Z210 CMT Workstation (Xeon E3, Core i3 and Intel Pentium processors), Z400 Workstation (4 DIMM Slots), Z400 Workstation (6 - Walmart.com
Solved: Z400 RAM - HP Support Community - 8063449
Solved: Z400 RAM - Page 2 - HP Support Community - 6148900