HP ProDesk 405 G4 Desktop Mini

Desktop, from 2020 2 hardware reports
Memory
Up to 16 GB
2 laptop-size slots
SSD
1+ M.2
At least 1 M.2 SSD slot
Drives and power
Coming next
Checked from separate sources

Only 2 machines reported so far, so this answer rests on few examples. Check the label or open the panel before you buy.

Upgradable

Yes. 2 slots, up to 16 GB seen working.

It takes DDR4-2400 laptop-size sticks (SO-DIMM).

Slots
2 SO-DIMM slots
Type
DDR4-2400 260-pin SO-DIMM
Most seen working
16 GB; one machine runs 16 GB
Firmware says
32 GB maximum
SSD slots
At least 1 M.2 SSD slot listed by the firmware
How sure
2 of 2 reports show this layout
See 8 GB DDR4-2400 SO-DIMM on AmazonOpens an Amazon search for this exact spec.

Worked out from 2 hardware reports of this desktop. Sources and method. Updated 9 Nov 2026.

2 laptop-size slots
Illustration

Questions

Can I upgrade the RAM in the HP ProDesk 405 G4 Desktop Mini?

Yes. 2 slots, up to 16 GB seen working. It takes DDR4-2400 laptop-size sticks (SO-DIMM).

What type of RAM does the HP ProDesk 405 G4 Desktop Mini use?

DDR4-2400 laptop-size sticks (SO-DIMM, 260-pin).

Does the HP ProDesk 405 G4 Desktop Mini have an M.2 SSD slot?

Yes. The firmware lists at least 1 M.2 SSD slot, in 2 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 Desktop Mini.