RAM Update in Workstatino Z440 do not work - HP Support Community - 6881802
A-Tech 32GB Kit (2 x 16GB) for HP Z440 Workstation - DDR4 PC4-21300 2666Mhz ECC Registered RDIMM 2Rx4 - Server Specific Memory Ram (AT378360SRV-X2R2) at Amazon.com
A-Tech 32GB Kit (2 x 16GB) for HP Z440 Workstation - DDR4 PC4-21300 2666Mhz ECC Registered RDIMM 1Rx4 - Server Memory Ram Equivalent to OEM 872970-001 872837-091 867855-B21 840757-091 815098-B21 at Amazon.com
Refurbished: HP Z440 Workstation Desktop PC, Intel Xeon E5-1620 v3 3.5GHz, 32 GB DDR4 RAM, 1 TB SSD, Nvidia Quadro K2200, Windows 10 Pro Grade B - Newegg.com
parts-quick 16GB Memory for HP Z440 Workstation DDR4 PC4-17000 2133 MHz RDIMM RAM at Amazon.com
HP Z440 Workstation Memory Modules Cooling Fan Assembly 752561-001 C3598WH 748799-001 [748799-001] - $79.99 : Professional Multi Monitor Workstations, Graphics Card Experts