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
Renewed HP Z400 WorkStation Intel Xeon CPU W3520 8Gb RAM 500GB HDD DVI Windows 10 With 30 days Return, 90 Days Exchange
HP Z400 Workstation Xeon 3.3 GHz - HDD 500 GB RAM 8GB | Back Market
HP Z400 Xeon Computer Quad core W3520 @ 2.67 GHz 4 GB RAM 250 HDD Windows xp Pro | eBay
CMS 8GB (2X4GB) DDR3 10600 1333MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z400 Workstation for Server Only - B80 at Amazon.com
How to install 16GB of memory/ram into an HP Z400 Workstation - YouTube
2GB Memory for HP Workstation Z400 DDR3 PC3-10600E ECC UDIMM (PARTS-QUICK Brand) at Amazon.com
HP Z400 Workstation OVERCLOCK your RAM @1380MHz!! - YouTube
HP Z400 almost 48GB ram Upgrade + RamDisk Benchmarks - YouTube