HP EliteDesk 800 G9 Mini Upgrade Guide: RAM, SSD and CPU

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

This guide covers upgrading memory, storage and the processor in the HP EliteDesk 800 G9 Desktop Mini, which HP now calls the Elite Mini 800 G9 Desktop PC. The short answer: you can add up to 64 GB of DDR5 SO-DIMM memory, fit two M.2 NVMe SSDs, and swap the processor within HP's listed range.

At a glance

  • RAM: 2 DDR5 SO-DIMM slots, up to 64 GB total (2 x 32 GB), unbuffered non-ECC only.
  • Storage: 2 M.2 2280 NVMe slots (PCIe Gen 4 x4) plus an optional 2.5 inch SATA bay on some configurations.
  • CPU: socketed, and HP's lists cover 12th, 13th and 14th gen Core, up to 65 W.
  • Update the BIOS before moving to a 13th or 14th gen processor.
  • The M.2 2230 slot is for the Wi-Fi card, not storage.
SO-DIMM memory2 × DDR5 SO-DIMM · up to 64 GB total · 4800 MT/s
M.2 2280 NVMe slot2 × SSD M.2 2280 (NVMe)
2.5" drive bayHDD / SSD 2.5" (SATA)
CPU socket (LGA1700)LGA1700 · Core 12th gen, Core 13th gen, Core 14th gen · max 65 W
CPU · LGA1700max 65 W2 × SO-DIMM · DDR5up to 64 GB totalM.2 2280 NVMe slot2 × SSD M.2 2280 (NVMe)2.5" drive bayHDD / SSD 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 (RAM): 2 DDR5 SO-DIMM slots, up to 64 GB

The Mini has two SO-DIMM slots, both user-accessible, and no soldered memory is mentioned. It takes unbuffered, non-ECC DDR5 only. Modules must be built with x8 or x16 memory chips; x4 modules are not supported and may stop the system working properly. HP lists configurations of 8 GB, 16 GB (1 x 16 or 2 x 8), 32 GB (1 x 32 or 2 x 16) and 64 GB (2 x 32).

The memory is rated at 4800 MT/s. Some models ship with 5600 modules, but HP notes that system speed may be lower, up to 4400 MT/s, depending on the configuration. HP says the two modules in a channel must be symmetric and recommends identical modules (same capacity, part number and supplier) for best speed.

Buying tips

  • Buy DDR5 SO-DIMMs (the laptop-size stick), non-ECC and unbuffered.
  • Check that the module uses x8 or x16 chips; avoid x4 modules. If the listing doesn't say, ask the seller.
  • Buy a matched pair for both slots rather than mixing brands or sizes.
  • Don't expect more than 4800 MT/s: faster modules may run at a lower speed in this system.
  • Check your model's shipped RAM speed (4800 or 5600) before comparing like for like.

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Storage: two M.2 NVMe slots and an optional 2.5 inch bay

There are two M.2 2280 slots for NVMe SSDs, each PCIe Gen 4 x4. HP lists M.2 SSDs up to 2 TB, but that is the largest size HP lists, not a stated maximum. Larger drives may work but aren't documented. One HP spec sheet mentions a Gen5 SSD, which conflicts with HP's Gen 4 slot specification; treat the slots as Gen 4. A Gen 4 drive is the safe choice.

Some configurations also have an optional 2.5 inch SATA bay. HP lists a 1 TB 7200 RPM hard drive for it, and an SSD of the same size also fits the bay. The bay isn't available if the machine was ordered with a discrete graphics card. HP's documents don't state a thickness limit for 2.5 inch drives, so check your unit before buying a thick drive.

The separate M.2 2230 slot is for the Wi-Fi card and shouldn't be counted as storage. The Mini has no 3.5 inch bay.

Buying tips

  • Buy an M.2 2280 NVMe drive, not a SATA M.2 drive.
  • A Gen 4 NVMe SSD is the best match; a faster Gen 5 drive gains nothing in a Gen 4 slot.
  • Open the case and check whether your unit has the 2.5 inch bay and cable before buying a SATA drive.
  • If you're keeping the old SSD, a second M.2 slot lets you add a drive instead of replacing one.

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Processor (CPU): socketed, within HP's listed range

The processor is in a socket, not soldered; HP's service manual includes a removal procedure for it. HP's documents don't name the socket; these CPUs use LGA1700. HP lists 12th, 13th and 14th gen Core processors. HP's support page names the 14th gen Core i5-14500, i7-14700 and i9-14900, with the i3-14100 and T versions also listed. The lists we found may be incomplete, so check HP's pages for your exact model.

Stay within HP's listed models. Support covers 65 W standard parts and 35 W T parts, and firmware decides which CPUs will boot. For 13th and 14th gen parts, update the BIOS before swapping the processor. HP doesn't publish a minimum BIOS version per CPU that we could find, so check HP's driver page for your unit.

Power and cooling need a check. The Mini uses an external power adapter of 90, 120, 150 or 180 W depending on configuration, and HP's documents don't say which adapter pairs with which CPU. If you move to a 65 W part, make sure your unit has a higher-wattage adapter. HP's service manual lists spare processors only in the 35 W T class, and HP's thermal limits for this chassis aren't published, so a 65 W part depends on the heat sink and fan in your configuration.

Buying tips

  • Choose a CPU from HP's own list for this model; unlisted CPUs may not boot.
  • Pick a 35 W T part if you want the safest fit for cooling and power.
  • Check the wattage printed on your power adapter before buying a 65 W CPU.
  • Update the BIOS first if you're moving to a 13th or 14th gen chip.
  • Have thermal paste ready, since the heat sink comes off to reach the CPU.

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How to upgrade

Before you start

  • Back up your files; a drive swap will need a reinstall or a clone.
  • Check your exact model's configuration (RAM speed, SSD type, whether it has the 2.5 inch bay and which power adapter).
  • Update the BIOS first if you are fitting a 13th or 14th gen CPU.
  • Read HP's service guide for exact disassembly steps for your unit.
  • Check your warranty: HP says Customer Self-Repair isn't available in all regions, and fitting an unsupported part can void the warranty.

Steps

  1. Back up and prepare
    Back up your data, note any encryption or BitLocker recovery keys, and update the BIOS if you're changing the CPU.
  2. Power off and unplug
    Shut the PC down fully, then unplug the power adapter and all cables. Hold the power button briefly to discharge any remaining power.
  3. Ground yourself
    Work on a clean, flat surface and touch bare metal or use an anti-static strap before handling parts. Hold modules and drives by their edges.
  4. Open the case
    Remove the access panel as shown in HP's service guide. For a CPU swap you also remove the fan and heat sink first.
  5. Install the new part
    For RAM, fit the SO-DIMMs in both slots, using a matched pair. For storage, fit the M.2 2280 SSD in one of the two storage slots, not the Wi-Fi slot, or fit a 2.5 inch drive in its bay. For a CPU, pull the locking lever, open the retainer, lift out the old processor and seat the new one. Don't touch the socket pins: damage may mean replacing the system board.
  6. Refit the heat sink and close up
    If you changed the CPU, reinstall the heat sink within 24 hours of fitting the processor, as HP warns that waiting longer can damage the solder connections. Then refit the fan and access panel.
  7. Check that the BIOS sees the part
    Reconnect power and start the PC. Open the BIOS setup or system information screen and confirm the new memory size, drive or processor is detected. If you changed the CPU, HP says to update to the latest BIOS. Then install or clone your operating system if needed.

Good to know

  • HP's documents disagree on speeds: some models ship with DDR5-5600 modules, others with 4800, and HP says system speed may be up to 4400 MT/s.
  • One spec sheet lists a Gen5 SSD, but HP's slot specification is PCIe Gen 4 x4. Treat the slots as Gen 4.
  • The 2.5 inch bay is optional and unavailable if the PC has a discrete graphics card. HP doesn't state a drive thickness limit.
  • HP's documents don't name the CPU socket, supported generations or a minimum BIOS version per CPU, and don't give a turbo power limit for this chassis. The CPU lists we found may be incomplete, so check HP's pages for your exact model.
  • HP doesn't say which power adapter suits which CPU, and its spare-part list for this model covers only 35 W T processors. Check your adapter and cooling before fitting a 65 W part.
  • HP says Customer Self-Repair isn't available in all regions, and fitting an unsupported part can void the warranty.

Frequently asked questions

How much RAM can the HP EliteDesk 800 G9 Mini take?

Up to 64 GB, using two 32 GB DDR5 SO-DIMMs. HP lists configurations of 8, 16, 32 and 64 GB.

Does the EliteDesk 800 G9 Mini use DDR5?

Yes. It takes unbuffered, non-ECC DDR5 SO-DIMMs built with x8 or x16 chips. DDR4 modules won't fit, and x4 modules aren't supported.

What speed will my memory run at?

The memory is rated at 4800 MT/s. Some models ship with 5600 modules, but HP notes that system speed may be lower, up to 4400 MT/s, depending on the configuration.

Can I add a second SSD?

Yes. There are two M.2 2280 NVMe slots (PCIe Gen 4 x4). Some configurations also have an optional 2.5 inch SATA bay, which isn't available if the PC has a discrete graphics card. The M.2 2230 slot is for the Wi-Fi card.

What is the biggest SSD it supports?

HP lists M.2 SSDs up to 2 TB, but that isn't a stated maximum. Larger drives may work but aren't documented.

Can I upgrade the CPU in the EliteDesk 800 G9 Mini?

Yes, the processor is socketed. HP lists 12th, 13th and 14th gen Core parts: 65 W standard and 35 W T versions. HP's documents don't name the socket; these CPUs use LGA1700. Update the BIOS before fitting a 13th or 14th gen chip, and stay within HP's listed models.

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.