HP EliteDesk 800 G4 Mini Upgrade Guide: RAM, SSD and CPU

Updated Oct. 9, 2026 · Written from this device's verified specifications

This guide covers adding memory, storage and a faster processor to the HP EliteDesk 800 G4 Desktop Mini (also sold as the 800 G4 DM). The short answer: you can go up to 32 GB of DDR4 SO-DIMM memory, fit two M.2 NVMe drives plus one 2.5 inch SATA drive, and swap the processor for another 8th-generation part rated 65 W or less.

At a glance

  • RAM: 2 DDR4 SO-DIMM slots, up to 2 x 16 GB (32 GB total), non-ECC only
  • Storage: two M.2 slots for 2230 or 2280 NVMe drives, plus one 2.5 inch SATA bay
  • A third M.2 2230 slot is for the Wi-Fi card, so it is not a storage slot
  • CPU: socketed, 8th-gen Core, Pentium Gold and Celeron, 65 W as the practical ceiling
  • Several HP documents cover the wider 800 G4 family, so check a spec applies to the Mini
DDR4 SO-DIMM memory2 × DDR4 SO-DIMM · up to 32 GB total · 2666 MT/s
M.2 storage slot (2230/2280)2 × SSD M.2 2230 / M.2 2280 (NVMe)
2.5" SATA baySSD / HDD 2.5" (SATA)
CPU socket (LGA1151, Q370)LGA1151 (8th/9th gen) · Core 8th gen · max 65 W
CPU · LGA1151 v2max 65 W2 × SO-DIMM · DDR4up to 32 GB totalM.2 storage slot (2230/2280)2 × SSD M.2 2230 / M.2 2280 (NVMe)2.5" SATA baySSD / HDD 2.5" (SATA)
Schematic of the upgradeable slots (not to scale). Check the owner's manual for their exact positions.

Lifecycle and support

No lifecycle information available.

Memory: 2 SO-DIMM slots, 32 GB maximum

The Mini has two user-accessible DDR4 SO-DIMM (laptop-size) slots, one per memory channel, and no soldered memory. HP's documents list a largest configuration of 2 x 16 GB, so 16 GB per module and 32 GB in total is the limit. Some third-party sellers claim 64 GB, but HP does not back that for the Mini. The 64 GB figure in HP's papers applies to the larger four-slot models.

Only unbuffered, non-ECC memory works. HP says modules built with x8 or x16 DRAM chips are supported and x4 chips are not. Single- or double-sided modules are fine. Chip densities of 2, 4, 8 and 16 Gbit are listed.

Speed is where HP's documents disagree. The support page, QuickSpecs and datasheet say 2666 MT/s, while the service guide describes the memory as DDR4-2400. Treat 2666 as the top rated speed, but don't be surprised if your modules run slower. HP's documents don't say whether the installed processor affects this.

Buying tips

  • Buy DDR4 SO-DIMM, non-ECC, unbuffered, 260-pin, 1.2 V
  • Choose 2 x 16 GB at most, and don't pay extra for a 64 GB claim
  • Avoid modules built with x4 DRAM chips; if the seller doesn't list chip type, ask
  • Matched pairs are simplest, since each slot sits on its own channel
  • HP recommends its own memory for guaranteed compatibility

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Storage: two M.2 NVMe slots and one 2.5 inch SATA bay

There are two PCIe x4 M.2 slots for storage, and each takes a 2230 or 2280 drive. HP's documents only mention NVMe drives for these, so SATA M.2 drives are unconfirmed. The PCIe generation is not stated either. The Q370 chipset suggests PCIe 3.0, but that is not confirmed by HP's papers. A third M.2 2230 slot holds the Wi-Fi card, so don't count it as storage.

The Mini also has one 2.5 inch SATA bay for an SSD or hard drive. HP's documents don't give a thickness limit for it, so check the drive's height before you buy. There is no 3.5 inch bay on the Mini. The 3.5 inch options on HP's support pages belong to the Workstation Edition.

HP doesn't state a maximum capacity per slot. Factory options top out at 2 TB for a 5400 rpm hard drive, 1 TB for NVMe and 512 GB for SATA SSD, but those are factory configurations, not hard limits.

Buying tips

  • Choose an NVMe M.2 drive in 2230 or 2280 length for the M.2 slots
  • Avoid SATA-only M.2 drives; compatibility is unconfirmed
  • Keep the 2.5 inch bay for SATA drives only
  • Check the thickness of any 2.5 inch drive, because the bay's limit isn't published
  • Leave the Wi-Fi card in its own M.2 2230 slot

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Processor: socketed, 8th-gen, 65 W ceiling

HP's documents don't name the socket. These Mini PCs use an Intel Q370 chipset (confirmed in the datasheet), which is normally paired with an LGA1151 socket. Verify the socket and exact processor compatibility before buying.

The datasheet lists 8th-generation Core, Pentium Gold and Celeron processors, in 35 W and 65 W versions. HP's spec page title mentions 35 W, 65 W and 95 W variants, but the 95 W parts most likely belong to larger models. Treat 65 W as the practical limit for this small chassis, which ships with a 90 W external power adapter. Whether 9th-generation processors work is not confirmed by HP's documents.

Buying tips

  • Stick to 8th-gen Core, Pentium Gold or Celeron parts rated 65 W or less
  • Avoid 95 W parts such as K-series chips
  • 35 W T-series parts are listed and suit the small case
  • Confirm the socket and compatibility before you buy
  • Don't assume a 9th-gen chip will work

How to upgrade

Before you start

  • Check which model you own. HP's 800 G4 family also includes SFF, TWR, All-in-One and Workstation versions, and some documents cover them all.
  • Back up your files before opening the PC or swapping drives.
  • Have the owner's manual or HP's service guide to hand for exact disassembly.
  • Note your current RAM, drive and processor details so you can confirm the new parts are recognised.
  • Use a clean, static-free work surface and a small screwdriver.

Steps

  1. Back up your data
    Copy important files to an external drive or cloud storage, especially if you are replacing or cloning a drive.
  2. Power off and unplug
    Shut the PC down fully, then unplug the power adapter and all cables. Hold the power button for a few seconds to drain any leftover charge.
  3. Ground yourself
    Touch bare metal on the case or wear an anti-static strap before handling components, and hold parts by their edges.
  4. Open the case
    Follow the opening procedure in the owner's manual or HP's service guide for the 800 G4 Desktop Mini. Disassembly details differ between models, so don't rely on the larger 800 G4 desktops.
  5. Install the new part
    For memory, fit the SO-DIMMs into the two slots. For storage, fit an M.2 drive in one of the two storage slots, or a drive in the 2.5 inch bay. Leave the Wi-Fi card in its M.2 2230 slot. For a processor, only fit a part you have confirmed is compatible, following the service guide.
  6. Close up and reconnect
    Refit any covers and screws, then reconnect the cables and power.
  7. Check the BIOS
    Turn the PC on and open the BIOS setup screen. Confirm it shows the new memory size, drive or processor. If a part is missing, power off, unplug and reseat it. If it still isn't recognised, check compatibility before trying again.

Good to know

  • Several HP documents cover the wider 800 G4 family (SFF, TWR, Workstation), so check which model a spec applies to.
  • HP's documents disagree on memory speed: 2666 MT/s on most pages, 2400 in the service guide.
  • The datasheet file is named for an EliteBook but its content describes the EliteDesk Mini.
  • SATA M.2 drive support, the PCIe generation of the storage slots and the 2.5 inch drive thickness limit are not stated.
  • The processor socket isn't named in HP's documents, and 9th-gen support is unconfirmed; verify before buying a CPU.

Frequently asked questions

How much RAM can the HP EliteDesk 800 G4 Mini take?

32 GB, as two 16 GB DDR4 SO-DIMMs. Some third-party sellers claim 64 GB, but HP's documents don't support that for the Mini.

What speed of RAM does it support?

HP lists DDR4-2666 (2666 MT/s) on its support page, QuickSpecs and datasheet. The service guide describes the memory as DDR4-2400, so treat 2666 as the top rating and expect that your modules may run slower.

Does it support NVMe SSDs?

Yes. It has two PCIe x4 M.2 slots for storage that take 2230 or 2280 drives. HP's documents only mention NVMe drives for these, so SATA M.2 drives are unconfirmed. The PCIe generation is not stated.

Can I add a 2.5 inch drive as well as M.2 drives?

Yes. There is one 2.5 inch SATA bay for an SSD or hard drive, but HP's documents don't give a maximum drive thickness. There is no 3.5 inch bay.

Can I upgrade the processor?

The processor is socketed. HP's datasheet lists 8th-gen Core, Pentium Gold and Celeron parts in 35 W and 65 W versions, and 65 W is the practical ceiling. HP's documents don't name the socket; these Q370 systems normally use LGA1151, so verify before buying.

Is the third M.2 slot usable for storage?

No. The third M.2 2230 slot is for the Wi-Fi card, so only two M.2 slots are for storage.

Official documents and references

This guide was written with AI assistance from the compatibility data PartsPrices verified against the manufacturer's documents. Always check your exact model and the owner's manual before buying or opening your computer.