HP ProDesk 405 G4 SFF
Desktop, from 2021 3 hardware reports
Memory

Up to 24 GB
4 full-size slots
SSD

1+ M.2
At least 1 M.2 SSD slot
Drives and power
Coming next
Checked from separate sources
Upgradable
Yes. 4 slots, up to 24 GB seen working.
It takes DDR4-2133 full-size sticks (DIMM).
- Slots
- 4 DIMM slots
- Type
- DDR4-2133 288-pin DIMM
- Most seen working
- 24 GB; one machine runs 24 GB
- Firmware says
- 64 GB maximum
- SSD slots
- At least 1 M.2 SSD slot listed by the firmware
- How sure
- 3 of 3 reports show this layout
See 4 GB DDR4-2133 DIMM on AmazonOpens an Amazon search for this exact spec.
Worked out from 3 hardware reports of this desktop. Sources and method. Updated 9 Nov 2026.

4 full-size slots
Illustration Questions
Can I upgrade the RAM in the HP ProDesk 405 G4 SFF?
Yes. 4 slots, up to 24 GB seen working. It takes DDR4-2133 full-size sticks (DIMM).
What type of RAM does the HP ProDesk 405 G4 SFF use?
DDR4-2133 full-size sticks (DIMM, 288-pin).
Does the HP ProDesk 405 G4 SFF have an M.2 SSD slot?
Yes. The firmware lists at least 1 M.2 SSD slot, in 3 reports. Some firmware leaves a slot out, so there may be more.
Is this my desktop?
Check the model name on the front or the label of the case. It should read ProDesk 405 G4 SFF.