HP EliteBook 840 G4 upgrade guide: RAM, SSD and CPU

Updated Oct. 12, 2026 · Written from this device's verified specifications

Thinking about adding memory, a bigger SSD or a faster processor to your HP EliteBook 840 G4? Two of those three are easy wins. This notebook takes up to 32 GB of DDR4 memory in two SO-DIMM slots and can run two drives at once - a 2.5-inch SATA drive and an M.2 NVMe SSD. The processor, however, is soldered down and cannot be swapped. One caution before you buy anything: the EliteBook 840r G4 is a different machine with its own specifications. Check the model printed on your notebook (and the Z2Z model code, e.g. 1CZ97EA) so you order parts for the right laptop.

At a glance

  • RAM: 2 SO-DIMM slots, up to 2 x 16 GB = 32 GB, DDR4 running at 2133 MT/s
  • Storage: 2.5-inch 7 mm SATA bay plus M.2 2280 (NVMe or SATA), both usable at the same time
  • CPU: soldered 7th Gen Intel Core U-series - not upgradeable
2× DDR4 SO-DIMM (user-accessible)2 × DDR4 SO-DIMM · up to 32 GB total · 2133 MT/s
2.5" 7 mm SATA bay + M.2 2280 slot2 × SSD / HDD SO-DIMM (SATA / NVMe) · max 7 mm thick
2 × SO-DIMM · DDR4up to 32 GB total2.5" 7 mm SATA bay + M.2 2280 slot2 × SSD / HDD SO-DIMM (SATA / NVMe) · max 7 mm thick
Schematic of the upgradeable slots (not to scale). Check the owner's manual for their exact positions.

Lifecycle and support

A current model: sold new and supported.

20172018201920202021202220232024202520262027Today11 · Release · 2017
Filled dots: dates published by the manufacturer. Hollow dots: estimates from third-party sources.
MilestoneDate
Release
First available to buy.		 2017 Official HP's own Maintenance and Service Guide (First Edition: December 2016, part no. 914960-001) states 'Planned availability – first quarter 2017' (for the HP Sure View option); the platform launched with the Dec 2016/Jan 2017 commercial refresh. HP publishes no month- or day-precise launch date, so this
Source ↗

Dates not listed haven't been published by the manufacturer or a reliable third party.

RAM upgrade

There are two DDR4 SO-DIMM slots, both accessible to you, and nothing is soldered to the board. That makes the maximum straightforward: 2 x 16 GB = 32 GB is the real ceiling, since the largest supported module is 16 GB.

Any standard DDR4 notebook SO-DIMM fits - unbuffered, non-ECC, non-registered. Server or ECC memory is not supported.

On speed, HP's documents don't fully agree. HP lists modules branded DDR4-2400 but states transfer rates of up to 2133 MT/s, while some HP materials simply say DDR4-2133. In practice, the Kaby Lake-U memory controller runs everything at 2133 MT/s, so DDR4-2133 and DDR4-2400 sticks both work at that speed. Buying faster-rated memory gives you no benefit here.

Two things to watch. First, update the BIOS before you install new memory - HP explicitly warns that skipping this can cause system problems. Second, if you fit only one module, it must go in socket 1, the primary socket marked on the motherboard. For dual-channel performance, use a matched pair of the same size and speed; a mismatched pair works but runs at the slower speed.

Buying tips

  • Buy DDR4-2133 or DDR4-2400 SO-DIMMs - both run at 2133 MT/s, so don't pay extra for 2666 or faster.
  • Matched pairs (2 x 8 GB or 2 x 16 GB) give you dual-channel speed; 32 GB means two 16 GB modules.

Cheapest compatible right now

See all compatible parts and prices →

Storage upgrade

You get two storage options and can use both at the same time.

The 2.5-inch bay takes SATA-3 hard drives or SSDs up to 7 mm thick. This limit is firm: 9.5 mm drives physically will not fit.

The second slot is an M.2 2280 (key M) that accepts either a PCIe Gen3 x4 NVMe SSD or a SATA M.2 SSD. A Gen4 NVMe drive will work, but only at Gen3 speed. Because the slot takes both types, check what you're buying: an M.2 SATA drive fits but won't deliver NVMe performance.

On capacity, HP validated drives up to 512 GB in the M.2 slot and up to 1 TB in the 2.5-inch bay. Larger drives - 1 TB or 2 TB M.2 modules, for example - commonly work, but they're outside HP's validated list, so compatibility isn't guaranteed.

Watch out for two things. SSD-only configurations of this laptop often shipped without the 2.5-inch drive cable and caddy, so if you want a dual-drive setup, check for those parts first (HP sells them as spares). Also note that the separate M.2 WWAN slot for an LTE module is not a storage slot - a drive won't work in it.

Buying tips

  • For the 2.5-inch bay, choose a 7 mm drive - 9.5 mm models won't fit.
  • For speed, an M.2 2280 NVMe drive is the fastest option; Gen3 drives cost less than Gen4 and perform the same here.

How to upgrade

Before you start

  • The right parts and the right machine: confirm yours is the EliteBook 840 G4 and not the 840r G4.
  • A screwdriver and an antistatic precaution - a grounded wrist strap or touching a bare metal surface before you handle the parts.
  • A current BIOS/firmware, downloaded and installed before you open the case (HP specifically warns about this for memory).

Steps

  1. Back up your data
    Copy anything important off the notebook before you touch the hardware. Storage swaps can mean reinstalling your system or cloning a drive, and memory changes can stop a machine booting if something is wrong.
  2. Update the BIOS and firmware first
    Install the latest BIOS from HP before fitting new memory. HP warns that skipping this step can result in system problems.
  3. Power down and disconnect
    Shut the notebook down fully, unplug the AC adapter and disconnect any peripherals. Make sure it is off, not asleep.
  4. Ground yourself
    Work on a clean, non-static surface and discharge any static in your body before touching memory modules or drives.
  5. Open the case
    Open the bottom of the notebook to reach the memory slots and storage bays. The exact screw locations and removal sequence are in HP's Maintenance and Service Guide for this model - use that document for the disassembly steps rather than guessing.
  6. Install the parts
    For memory: seat each SO-DIMM firmly at an angle and press it down until the clips lock. A single module must go in socket 1, the primary slot marked on the board; use a matched pair for dual-channel. For storage: slide the M.2 2280 drive into its slot and secure it, and fit a 2.5-inch drive in the bay - if your notebook is an SSD-only model, you may need the SATA cable and caddy from HP spares first.
  7. Close the case
    Refit the cover and screws the way they came out. Check that nothing is trapped and that drive cables are seated properly.
  8. Check the BIOS
    Power on and enter the BIOS to confirm the machine sees the new memory capacity and the drive. If it doesn't, reseat the part and re-check. Then let your operating system finish loading before you start restoring data.

Good to know

  • Capacity limits beyond what HP validated (512 GB M.2, 1 TB HDD) are commonly reported to work but are not guaranteed.
  • Documents disagree on the memory speed label (DDR4-2400 vs DDR4-2133); both run at 2133 MT/s in this machine.

Frequently asked questions

How much RAM can the HP EliteBook 840 G4 take?

32 GB, as 2 x 16 GB DDR4 SO-DIMMs. Nothing is soldered to the board, so both slots are yours to use. 16 GB is the largest single module supported.

Do I need DDR4-2400 or DDR4-2133 memory?

Either works. HP brands modules as DDR4-2400 while stating transfer rates up to 2133 MT/s, and some HP documents say DDR4-2133 outright. Everything runs at 2133 MT/s, so don't pay extra for faster-rated memory.

Does the EliteBook 840 G4 support NVMe SSDs?

Yes. The M.2 2280 slot accepts PCIe Gen3 x4 NVMe drives as well as SATA M.2 drives. Gen4 NVMe drives work too, but only at Gen3 speed.

Can I run two drives at the same time?

Yes - a 2.5-inch SATA drive and an M.2 SSD simultaneously. Just check that your machine has the 2.5-inch drive cable and caddy, since SSD-only configurations often shipped without them.

Can I upgrade the CPU on the EliteBook 840 G4?

No. The processor is soldered down (BGA 1356), so there is no socket and no way to fit a faster chip. Your machine keeps the 7th Gen Intel Core U-series processor it was built with.

Is the EliteBook 840r G4 the same laptop?

No - it's a different model with its own specifications. Check the exact model name and code on your notebook before ordering parts.

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.