HP ZBook 15 G5 Mobile Workstation upgrade guide: RAM, SSD and CPU

Lifecycle and support

No longer sold new. The manufacturer hasn't published an end-of-support date.

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

Memory (RAM)

All memory in the ZBook 15 G5 is modular - nothing is soldered to the board. There are four DDR4 SO-DIMM slots, but HP designates only two of them as customer-accessible. Reaching the other two means removing the keyboard/top deck, which is a bigger job; allow time for it or have a technician do it.

The machine takes DDR4 SO-DIMMs rated at 2666 MT/s in dual-channel configuration. None of the memory is registered or buffered. How much total memory you can install depends on which processor your unit has:

Core i5/i7 models use non-ECC memory. HP's technical data sheet and Kingston both list 128 GB as achievable here, using 32 GB SO-DIMMs.

Xeon models (E-2176M/E-2186M) require unbuffered ECC SO-DIMMs and top out at 64 GB. ECC and non-ECC modules cannot be mixed in the same machine, so match whatever is already installed.

Be aware that HP's own documents disagree on the ceiling. The service manual states 64 GB using 16 GB modules, while HP's later data sheet and Kingston's configurator list 128 GB with 32 GB modules on Core systems. If you want more than 64 GB, buy a Core (non-Xeon) unit and confirm your BIOS recognises 32 GB modules before you commit.

Speed is another grey area. 2666 MT/s is the nominal spec, but some HP documents say two-module configurations run at 2400 MT/s and four-module configurations at 2133 MT/s, while Kingston says four-module setups run at 2400 MHz. Expect the system to downclock as you populate more slots, and check the reported speed in the BIOS afterwards.

Buying tip: order modules in matched pairs of the same size and speed - dual-channel performance depends on it. And update the BIOS before you fit the new memory: HP explicitly warns that installing memory on older firmware can cause system problems.

Buying tips

• Matched pairs, same capacity and speed, for dual-channel performance
• Non-ECC for Core i5/i7 units; unbuffered ECC only for Xeon units - never mix the two
• Update the BIOS before installing the modules

Storage (SSD and HDD)

There are three storage positions in this machine.

Two M.2 2280 slots (22 x 80 mm). Either one accepts a SATA-3 SSD or a PCIe NVMe Gen3 x4 SSD - the choice is yours, no minimum PCIe generation is specified. HP lists drives up to 2 TB per slot. In practice the NVMe options in HP's own configurations are TLC drives around the 2600-2900 MB/s read range, so a modern Gen3 NVMe drive is a sensible match.

One optional 2.5-inch SATA bay. This takes 7.0 mm or 9.5 mm drives - hard disks, hybrid drives or SATA SSDs. HP lists 2 TB as the largest HDD option (5400 rpm), with 7200 rpm 1 TB and SED/FIPS drives among the alternatives. The bay is not fitted on every unit: HP notes that primary 2.5-inch storage is not required when a PCIe SSD is configured, and in those systems the bay may be absent. Check inside your own machine before ordering a 2.5-inch drive.

A few details worth knowing before you shop. The optional 16 GB Intel Optane cache works only when the system is configured with a 2.5-inch hard disk - it does nothing for an all-SSD setup. RAID 0 and RAID 1 are supported, but only across SATA drives, so don't plan a RAID array of two NVMe SSDs. And expect less usable space than the label suggests: HP notes that a gigabyte is a billion bytes and that up to 30 GB is reserved for Windows recovery.

Buying tip: for the biggest everyday speed-up, put your operating system and applications on an NVMe Gen3 x4 M.2 2280 drive and use the remaining M.2 slot or the 2.5-inch bay for bulk storage. Any M.2 SSD you buy should be 2280 size; smaller 2242 or 2230 drives are not the format these slots are built for.

Buying tips

• M.2 2280 only - SATA-3 or NVMe Gen3 x4 both fit the two M.2 slots
• Check the 2.5-inch bay actually exists in your unit before buying a hard disk or SATA SSD
• Keep HDD thickness to 7 or 9.5 mm

How to upgrade

Before you start

• Back up your data first - a failed install or a drive that needs reinitialising shouldn't cost you files.
• Shut the system down fully and unplug the power adapter (and any dock).
• Ground yourself to discharge static - a grounded wrist strap is ideal; at minimum work on a hard, non-carpeted surface and touch bare metal before handling parts.
• Update the BIOS/firmware before installing new memory - HP warns that memory installed on older firmware can cause problems.
• Open the case following the owner's manual; the exact screws, clips and release points are model-specific and HP documents them step by step.
• Install the part, close the case, reconnect power and start up.
• Check that the BIOS/firmware reports the new memory or drive correctly, and note the RAM speed actually being used.
• If you are reaching the two buried memory slots under the keyboard/top deck, weigh the effort - it is a deeper disassembly than the easy-access upgrade.

Steps

1. RAM
   Two of the four SO-DIMM slots are designed to be customer-accessible and are the easy route. The other two require removal of the keyboard/top deck. Push each module in at a slight angle and press it down until the side clips lock, and install matched pairs across both channels. Update the BIOS first - HP specifically cautions about this. For the exact disassembly sequence and screw locations, follow HP's owner's/service manual for your unit.
2. Storage
   M.2 2280 SSDs slide into their slot and fasten at the end screw; the 2.5-inch drive (if your unit has the bay) sits in its carrier. Confirm the 2.5-inch bay is actually present before you start - it is omitted on some PCIe SSD configurations. Check in the BIOS that every drive is detected after reassembly. Exact procedures and screws are in HP's manual for this model.
3. CPU
   There is no procedure - the processor is soldered and cannot be replaced or upgraded.

Good to know

• HP's documents disagree on maximum memory: the service manual says 64 GB with 16 GB modules, while HP's data sheet and Kingston list 128 GB with 32 GB modules on Core systems.
• RAM speed sources differ: some HP documents say 2400 MT/s with two modules and 2133 MT/s with four; Kingston says four-module configurations run at 2400 MHz.
• The 2.5-inch bay is optional and may not be fitted in your unit - check before buying a hard disk or SATA SSD.
• The optional 16 GB Optane cache only works alongside a 2.5-inch hard disk.

Frequently asked questions

How much RAM can the HP ZBook 15 G5 take?

It depends on the processor. Core i5/i7 models take non-ECC DDR4 SO-DIMMs and HP's data sheet plus Kingston both list 128 GB using 32 GB modules. Xeon models require unbuffered ECC and cap at 64 GB. HP's older service manual states 64 GB overall, so documents disagree above 64 GB - verify BIOS support for 32 GB modules if you need more.

How many RAM slots does it have?

Four DDR4 SO-DIMM slots, all socketed. Two are customer-accessible; the other two require removing the keyboard/top deck to reach.

Does the ZBook 15 G5 support ECC memory?

Only on Xeon models (E-2176M/E-2186M), and it must be unbuffered ECC. Core i5/i7 units take non-ECC only, and ECC and non-ECC modules cannot be mixed.

What SSDs fit in the ZBook 15 G5?

Two M.2 2280 slots, each accepting either a SATA-3 SSD or a PCIe NVMe Gen3 x4 SSD, up to 2 TB per slot per HP. There is also an optional 2.5-inch SATA bay for 7 or 9.5 mm drives.

Can I add a second SSD?

Yes - there are two M.2 2280 slots, and a third position via the optional 2.5-inch SATA bay if your unit has it. Note that RAID 0/1 is only supported across SATA drives.

Can I upgrade the CPU in my ZBook 15 G5?

No. The processor is soldered to the mainboard, as is the discrete GPU. HP shipped this model with 8th-Gen Coffee Lake-H 45 W processors only - Core i5-8300H/8400H, Core i7-8750H/8850H and Xeon E-2176M/E-2186M - and no swap or generation upgrade is supported.

Official documents and references

• PDF HP ZBook 15 G5 Mobile Workstation - Maintenance and Service Guide (PDF)
  Official HP service manual: slot layout, memory and storage specifications, and disassembly procedures.
• PDF HP ZBook 15 G5 Mobile Workstation - Technical Data Sheet (PDF)
  HP's data sheet: configuration options, storage choices and memory configurations including 128 GB on Core models.
• Kingston memory configurator for the HP ZBook 15 G5
  Module compatibility by processor type (ECC/non-ECC), capacity limits and matched-pair guidance.
• HP Business Notebooks forum - RAM upgrade on ZBook 15 G5
  HP discussion on ECC vs non-ECC rules and what the different processor tiers accept.