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 at Amazon.com
HP Z400 almost 48GB ram Upgrade + RamDisk Benchmarks - YouTube
HP Z400 Workstation MT Intel Xeon W3550 3.07GHz 8GB RAM No HDD No OS
Solved: Z400 RAM - Page 2 - HP Support Community - 6148900
Used HP Additional 4GB 1866 MHz DDR3 ECC RAM Memory E2Q91AT B&H
Renewed HP Z400 WorkStation Intel Xeon CPU W3520 8Gb RAM 500GB HDD DVI Windows 10 With 30 days Return, 90 Days Exchange
HP Z400 8GB Computers - Windows 10 for Less | Build Your Workstation