12GB KIT (6 x 2GB) for HP-Compaq Z Workstation Series Z400 (6 DIMM Slots). DIMM DDR3 ECC Unbuffered PC3-10600E 1333MHz Server Ram Memory. Genuine A-Tech Brand. at Amazon.com
HP Z400 Workstation Desktop SSD Solid State Drive W/ Windows 10 64-Bit | eBay
Solved: Z400 Aftermarket Upgrades - HP Support Community - 5691838
Solved: Z400 X5690 W3690 Fastest Processors - Page 2 - HP Support Community - 5683601
HP Z400 Workstation Refurbished Desktop PC Intel Xeon 8GB Memory 1TB Hard Drive120GB Solid State Drive Windows 10 HZ400TX81120WP - Office Depot
This is my HP Z400, upgraded with a Xeon X5690. 12gb of ram, 2x500gb SSD, 2x250gb HDD, GTX 960 (the gpu is totally overkill lol). This is my first server! Running pterodactyl
Solved: SATA III (6gb) drive is officially supported on Z400 Worksta... - HP Support Community - 7370916
4GB RAM Memory Upgrade for HP Workstation Z400 PC3-10600E DDR3 1333MHz 2Rx8 ECC Unbuffered UB DIMM Module (PARTS-QUICK Brand) at Amazon.com
Managed to get an old HP Z400 workstation for the equivalent of $75 USD. Xeon W3520, 6x2gb of ram and I replaced the Quadro FX580 with a GT 730 I had laying around. I will add an SSD. : r/pcmasterrace
How to Upgrade a HP Z400 from a HDD to SSD and Solve winload.exe BSOD Error - YouTube
HP Z400 ATX 700W Power Supply Upgrade and Install - YouTube
HP Z400 Gaming Computer (GTX 1080 Ti and NVMe.2 Install) - YouTube
HP Z400 Workstation Memory/RAM & SSD Upgrades | Kingston