Fortunately the format is EATX so an EATX case will work and the screw layout is standard.
You will need to remove the HEX/TORX screws that are connecting the stock HP standoffs (meant to slide into an HP case).
XW9400 Motherboard Issues
Size: 12" x 13"
Proprietary Power Connector
Proprietary CPU Power Connector
Proprietary Memory Power Connector
Fan connectors are 4 pin so you will need some kind of adapter.
One very nice feature is that it has 6 SATA ports and a whopping 8 SAS ports as well (which of course can be used for SATA) if you really think you can use or fit 14 drives.
Case LED/Power/Reset Connections are not specified or mapped (can be done with trial and error)
The biggest dilemma is which way to go?
I could buy an HP Case but it is not clear which ones will fit (although most of the XW8 to XW9 series seem to appear the same). No matter what you do you will need an HP Power Supply unless you can hack your own adapter (for some servers like Z800 there is such an adapter but I have not found one for this board).
Power Supply Part#\'s (not verified)
Delta DPS1050CB 1050W HP P/N 440860-001 (SPARE) 442038-001
There also seems to be a lower wattage model from the XW8400 that is supposed to work.
Delta DPS-825AB B 800W Power Supply 405351-003
Link to HP Manual:
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