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used mini pcs

HP · 2018

HP ProDesk 400 G4 Desktop Mini

The ProDesk 400 G4 Desktop Mini is HP's 2018 entry-level 1-liter business PC, the cheaper sibling of the EliteDesk 800 G4. It shares the same small chassis but is limited to 35 W 8th-gen T-series CPUs from the Celeron G4900T to the six-core Core i7-8700T, with the i3-8100T and i5-8500T most common. It takes two DDR4 SO-DIMMs (32 GB official), one M.2 NVMe drive and a 2.5-inch SATA drive, and has a Realtek gigabit NIC with no vPro or AMT. The single NVMe slot and missing remote management are the trade-offs against the 800 G4. In return it's a quiet, low-power box for Home Assistant, Pi-hole, a small Plex server or a first Proxmox node. STH measured about 10-11 W at idle.

Good for

Badges come from the spec rules on each use page, not from guesswork.

HP ProDesk 400 G4 Desktop Mini in black and silver, three-quarter front view showing the hp logo, PRODESK lettering, two USB-A ports, audio jacks and power button
Representative photo — AI-generated from real seller photos. Individual listings vary. How we make these →

Specs that matter used

CPU generation
Intel 8th Gen (Coffee Lake / Whiskey Lake / Kaby Lake-R)
CPU options
Core i3-8100T, Core i5-8500T, Core i5-8600T, Core i7-8700T, Core i3-8300T, Pentium Gold G5400T, Celeron G4900T
Form factor
1-liter business mini
Released
2018
Memory
DDR4 SO-DIMM (HP part list: DDR4-2666 modules), 2 slots
Max RAM (official)
32 GB
Storage
1× M.2 2280/2230 PCIe NVMe + 1× 2.5-inch SATA bay (tray with four screws and vibration dampeners)
Ethernet
1 × 1 GbE (Realtek RTL8111 (no vPro). Optional rear port: DisplayPort, HDMI, VGA, USB-C or serial)
Wi-Fi
M.2 2230 slot; Intel 9560/7265/3168 or Realtek RTL8822BE/8821CE/8723DE were factory options
vPro / AMT
No
Cooling
Fan-cooled
Power adapter
HP external 19.5 V 65 W adapter (the only adapter in HP's parts list)
Measured idle draw
10–11 W (ServeTheHome measured 10-11 W idle at 120 V on a Core i3-8100T unit with a 65 W adapter; source)
Windows 11
CPU generation is on Microsoft's supported list
Spec sources

Check before you buy

General off-lease checks (BIOS passwords, Computrace, missing drive caddies) are in the used mini PC buying checklist.

Buying guide

Which one to buy

Oct 4, 2026

59 ProDesk 400 G4 Minis are listed, and most complete units run $120–320 delivered, with an i5-8500T, 8 GB and a 256 GB SSD from about $125. It's the budget sibling of the EliteDesk 800 G4: one NVMe slot, Realtek LAN and no vPro, and HP lists only a 65 W adapter for it, so make sure one is included. Skip Pentium Gold units with hard drives at i5 prices, and one seller's listings at two to four times the going rate.

Listed now
59
For parts
0
Typical ask
$120–$320
Full range
$60–$614

Snapshot

Live on eBay right now

8 of 59 listed

Snapshot captured — listings may have ended

Delivered prices include shipping as eBay quoted it to a US address on Oct 4, 2026. Many sellers charge by distance, so your total may differ; eBay shows your exact total before you buy.

Prices and availability change daily. The full, current search on eBay shows every matching listing, including new ones since Oct 4, 2026.

See all current listings on eBay ↗eBay search

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