HP EliteDesk 800 G5 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 G5 Desktop Mini (DM). The short answer: it has two SO-DIMM slots, two M.2 NVMe storage slots, a 2.5-inch SATA bay and a socketed 8th/9th gen Intel CPU. HP's documents disagree on the memory maximum, so 2 x 16 GB is the safe choice.

At a glance

  • RAM: 2 DDR4 SO-DIMM slots, non-ECC. HP lists both 64 GB and 32 GB maximums, so 2 x 16 GB is the safe pick.
  • Storage: 2 M.2 2230/2280 NVMe slots plus one 2.5-inch SATA bay, which may not be fitted on every unit.
  • A third M.2 2230 slot is reserved for the Wi-Fi card, so it is not for storage.
  • CPU: socketed 8th/9th gen desktop-class Intel chips on the Q370 chipset, from Celeron G4930 up to Core i9-9900/9900T.
  • HP doesn't state a CPU power limit, so check cooling before fitting a 65 W or K-series chip.
SO-DIMM memory slot2 × DDR4 SO-DIMM · up to 64 GB total · 2666 MT/s
M.2 2230/2280 storage slot2 × SSD M.2 2230 / M.2 2280 (NVMe)
2.5" SATA drive bayHDD / SSD 2.5" (SATA)
Socketed desktop CPU (Intel Q370)LGA1151 (8th/9th gen) · Core 8th gen, Core 9th gen
CPU · LGA1151 v22 × SO-DIMM · DDR4up to 64 GB totalM.2 2230/2280 storage slot2 × SSD M.2 2230 / M.2 2280 (NVMe)2.5" SATA 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.

RAM: two SO-DIMM slots, 32 GB is the safe target

The EliteDesk 800 G5 DM has two DDR4 SO-DIMM slots (260-pin, 1.2 V), labeled DIMM1 and DIMM3. Both are user-accessible and no memory is soldered to the board. Modules must be unbuffered and non-ECC, and built with x8 or x16 memory chips. HP's service guide says modules with x4 chips are not supported and warns the system may not work properly with unsupported modules.

HP's documents disagree on the ceiling. The datasheets say 64 GB (2 x 32 GB) at DDR4-2666. The service guide says 32 GB at DDR4-2400. HP's parts list shows only 4, 8 and 16 GB modules, in DDR4-2666 or DDR4-2400. Nothing HP publishes shows a 32 GB module, so 64 GB is unconfirmed. Two 16 GB modules (32 GB) are the option HP's own parts list supports.

The installed processor sets the memory speed the system actually runs at, so a DDR4-2666 kit may not run at 2666 with every CPU. A 32-bit operating system can't use more than 4 GB, so make sure you run a 64-bit one.

Buying tips

  • Buy DDR4 SO-DIMMs (laptop-size), not desktop DIMMs.
  • Choose unbuffered, non-ECC modules; avoid ECC and registered kits.
  • Look for modules built with x8 or x16 chips; x4-based modules are not supported. If the listing doesn't say, ask the seller.
  • Buy a matched pair of 2 x 16 GB rather than gambling on 32 GB modules.
  • If you still want 2 x 32 GB, check that the seller accepts returns, since HP doesn't list that size.

Cheapest compatible right now

See all compatible parts and prices →

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

Two M.2 slots take 2230 or 2280 NVMe SSDs. HP's datasheets list NVMe SSDs up to 2 TB, plus Intel Optane H10 options. A third M.2 2230 slot is reserved for the WLAN card, so leave it alone. HP's documents don't say whether the storage slots also accept SATA M.2 drives, or which PCIe generation they use. Stick with NVMe drives, and expect a faster PCIe drive may not run at its top speed.

There is also one 2.5-inch SATA bay. HP's configurations offer HDDs up to 2 TB (5400 or 7200 rpm) and 2.5-inch SATA SSDs of 256 to 512 GB, which indicates what works there. A 7 mm thickness limit looks likely but isn't confirmed, so a 7 mm drive is the safest choice. The bay may not be fitted on every unit, so check your configuration before buying a drive for it.

In total you can have at most three storage devices: two M.2 drives and one 2.5-inch drive, if your unit has the bay.

Buying tips

  • Pick an NVMe M.2 SSD in 2230 or 2280 length.
  • Avoid SATA-only M.2 drives; HP doesn't confirm they work in these slots.
  • For the 2.5-inch bay, a 7 mm SATA drive is the safest fit.
  • Check whether your unit actually has the 2.5-inch bay before buying a drive for it.
  • Don't plan on 2 TB-plus NVMe drives beyond what HP lists; 2 TB is the largest size HP's datasheets show.

Cheapest compatible right now

See all compatible parts and prices →

CPU: 8th and 9th gen desktop chips on the Q370 chipset

The processor is socketed and the board uses the Intel Q370 chipset (vPro and non-vPro variants). HP lists 8th and 9th gen desktop-class processors, from the Celeron G4930 and Pentium Gold G5420/G5600 up to the Core i9-9900 and 9900T, including i3, i5 and i7 parts. K-series models such as the i9-9900K and i7-9700K also appear on HP's list.

HP's documents don't name the socket or a maximum power rating. Q370 boards use LGA1151, so match that. Intel rates T-series chips at 35 W and standard chips at 65 W. HP sells separate 35 W and 65 W versions of this chassis, so whether your mini can cool a 65 W or K-series chip is not confirmed. Check the service guide and your exact model before buying.

A new CPU also affects memory speed, because the processor decides which RAM speeds are supported. Integrated graphics are Intel UHD 630 or 610 depending on the chip.

Buying tips

  • Only buy 8th or 9th gen desktop chips from HP's supported list.
  • If your mini is a 35 W model, a T-series chip (such as the i9-9900T) is the safer choice.
  • Be cautious with K-series and 65 W chips; cooling is unconfirmed.
  • Look for a chip with integrated graphics, since the board relies on it unless your unit has the optional discrete card.
  • Check the exact chip name against HP's supported list before you order.

How to upgrade

Before you start

  • Find your exact configuration (CPU, drives, memory, graphics) and the model number.
  • Download the Maintenance and Service Guide or owner's manual for exact disassembly steps.
  • Back up your files, and note any drive-encryption or recovery keys you rely on.
  • Have a small screwdriver and an anti-static wrist strap or a bare metal surface to touch.
  • Buy parts that match the limits in this guide, and keep the receipt in case something doesn't fit.

Steps

  1. Back up your data
    Copy important files to an external drive or cloud storage before you open the case, especially if you're replacing a drive.
  2. Shut down and unplug
    Shut the PC down fully (not sleep), unplug the power adapter and any cables, and press the power button once to drain leftover charge.
  3. Ground yourself
    Work on a clean, flat surface. Wear an anti-static strap or touch bare metal on the chassis before handling parts, and hold components by their edges.
  4. Open the case
    Remove the cover as shown in HP's owner's manual or service guide. Follow the manual for any latch, screw or internal panel.
  5. Install the new part
    For RAM, fit the SO-DIMMs into the two slots. For storage, fit an NVMe drive in one of the two storage M.2 slots (not the WLAN slot), or a SATA drive in the 2.5-inch bay. For a CPU, follow the service guide for removing the cooler and seating the new chip. Don't force anything.
  6. Close it up
    Refit any panels, the cooler or the drive bay parts you removed, then put the cover back on and reconnect the cables.
  7. Check the BIOS
    Turn the PC on and open the BIOS setup, as described in HP's manual. Confirm it shows the new memory total, the new drive or the new processor. For a new drive, you'll also need to install or restore an operating system.

Good to know

  • HP documents conflict on the memory maximum (64 GB at DDR4-2666 versus 32 GB at DDR4-2400); 64 GB with 32 GB modules is unconfirmed.
  • HP's documents don't say whether the M.2 storage slots accept SATA drives or which PCIe generation they use.
  • The 2.5-inch bay may not be fitted on every unit, and a 7 mm thickness limit is likely but unconfirmed.
  • HP's documents don't name the CPU socket or a power limit. These chips use LGA1151, and 65 W or K-series chips may exceed what your chassis can cool.
  • Units vary (Optane, encrypted drives, different CPUs and graphics), so check your exact configuration and HP's service guide before buying.

Frequently asked questions

How much RAM can the HP EliteDesk 800 G5 Mini take?

HP's documents disagree. The datasheets say 64 GB (2 x 32 GB), while the service guide says 32 GB. HP's parts list only shows modules up to 16 GB, so 2 x 16 GB (32 GB) is the safe choice. A 64 GB kit is unconfirmed.

What type of RAM does it use?

Two DDR4 SO-DIMM slots, unbuffered and non-ECC, with modules built from x8 or x16 chips. The datasheets quote DDR4-2666, the service guide quotes DDR4-2400, and the installed CPU sets the actual speed.

Can I add a second SSD?

Yes. There are two M.2 2230/2280 NVMe slots for storage, plus a 2.5-inch SATA bay on units that have it. A third M.2 2230 slot is reserved for the WLAN card.

Does it take SATA M.2 drives?

HP's documents don't say whether the M.2 storage slots accept SATA drives, so choose NVMe. They also don't name the PCIe generation.

Can I upgrade the CPU?

Yes, the processor is socketed. HP lists 8th and 9th gen desktop chips from the Celeron G4930 up to the Core i9-9900/9900T. HP doesn't state a power limit, so check cooling before fitting a 65 W or K-series chip.

Is the Wi-Fi slot usable for an SSD?

No. The extra M.2 2230 slot is reserved for the WLAN card.

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.