A-Tech 24GB ECC Unbuffered Memory Kit (6 x 4GB) for HP Z400 Workstation - ECC UDIMM DDR3 PC3-10600 1333MHz 240-Pin DIMM 2Rx8 1.5V Dual Rank RAM (AM080899) at Amazon.com
HP Z400 Computer Workstation 500 GB HD 6GB RAM Quadro FX 580 - Park Slope, NY Patch
Norton Racing Ninja400R Ram Air Kit - Kawasaki Ninja 400 / Z400
Solved: Z400 RAM - Page 2 - HP Support Community - 6148900
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