HP Z400 Workstation FL998U8 W3550 3.06GHz/ 8GB RAM/ 160GB HDD [Z400] - $395.00 : Professional Multi Monitor Workstations, Graphics Card Experts
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Solved: Z400 RAM Upgrade from 8GB to 12GB or 16GB - HP Support Community - 6746942
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HP Z400 Workstation MT Intel Xeon W3550 3.07GHz 8GB RAM No HDD No OS
32GB (4X8GB) DDR3 1333 Memory For HP Z400 Z420 Workstation | eBay