HP Z2 G4 Tower Workstation upgrade guide

Lifecycle and support

A current model: sold new and supported.

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

Memory (RAM)

The tower has 4 DDR4 DIMM slots and no soldered memory, so all of it is replaceable. These are full-size desktop DIMMs (288-pin), not the laptop-style SO-DIMMs.

What fits: DDR4 UDIMM (unbuffered) modules only. Registered memory (RDIMM/LRDIMM) will not work. Speeds up to 2666 MT/s. HP validated 32 GB modules, giving a maximum of 128 GB in total (4 x 32 GB).

Limits and watch-outs: Intel's published spec for these CPUs stops at 64 GB, while HP validated 32 GB DIMMs and 128 GB total. The BIOS support is there, but third-party 32 GB DIMMs aren't guaranteed to work — check the seller's return policy. Also, if your machine has a 2400 MT/s CPU (Core i3-8100 or Pentium G5400), memory runs at 2400 MT/s whatever module you buy, so don't pay extra for faster sticks.

ECC depends on the processor, not the board. Xeon E-2100/E-2200, Core i3 and Pentium chips accept ECC or non-ECC memory; Core i5/i7 (and i9) accept non-ECC only. ECC and non-ECC modules can't be mixed in one system. If your machine is a Core i5/i7/i9 build, the only way to gain ECC later is to swap in a Xeon E, i3 or Pentium CPU.

Buying tip: buy matched pairs and install them as pairs (DIMM1 and 3, then DIMM2 and 4) to keep both memory channels working. Match the modules in size and speed.

Buying tips

• Desktop DDR4 UDIMM only — not SO-DIMM, not registered memory
• Matched pairs, installed in the paired slots
• 32 GB DIMMs are HP-validated but third-party ones aren't guaranteed
• 2400 MT/s CPUs cap RAM at 2400 MT/s

Storage (SSD and hard drive)

The tower offers room for both 2.5/3.5-inch SATA drives and M.2 NVMe SSDs.

What fits: two internal 3.5-inch drive bays and two external half-height 5.25-inch bays (one usually holds the optical drive). There are 4 SATA 6 Gb/s ports in total, and one can optionally be routed as eSATA. Because the optical drive uses one port, a third or fourth SATA drive needs a 5.25-inch-to-3.5-inch carrier in one of the half-height 5.25-inch bays. Beyond four SATA drives you'll need a PCIe host bus adapter in an expansion slot.

There are also 2 M.2 slots running PCIe Gen3 x4 NVMe. Drives up to 110 mm long fit (2242, 2260, 2280 and 22110 lengths). M.2 SATA support is not clearly documented in HP's material — verify with the seller before buying an M.2 SATA SSD. The separate M.2 2230 slot is for a WLAN module and is not a storage slot.

Limits and watch-outs: HP publishes no per-bay capacity ceiling, so very large 3.5-inch drives physically fit the bays, but HP's own validated list tops out much lower — larger drives are your own risk. M.2 drives must be 110 mm or shorter. Intel RST RAID 0/1/5/10 is supported, and HP notes RAID 5 is not recommended with drives larger than 500 GB. If you install a PCIe storage card, remember that HP supports only HP-qualified cards in the Gen3 x16 slot for warranty purposes.

Buying tip: measure before you shop. If you want more than two SATA drives, budget for a 5.25-inch-to-3.5-inch carrier as well as the drive itself. For speed, a single M.2 NVMe SSD is the simplest upgrade — no cables and no bay needed.

Buying tips

• M.2 NVMe SSD, 110 mm or shorter (2242/2260/2280/22110)
• SATA drives: check your free ports — 4 total, one may be used by the optical drive
• A 5.25-to-3.5 carrier is needed for a 3rd or 4th SATA drive
• Verify M.2 SATA support before buying an M.2 SATA SSD

Processor (CPU)

The processor sits in a single socketed LGA 1151 slot on Intel's C246 chipset, so it can be replaced.

What fits: 8th-generation (Coffee Lake) and 9th-generation Intel Core i3/i5/i7/i9, Pentium Gold, and Xeon E-2100 and E-2200 processors. Availability of any given model varies by region and build-to-order configuration, so check HP's list for your market before buying.

Limits and watch-outs: update the system BIOS before removing the current CPU. Early BIOS revisions only support 8th-gen and Xeon E-2100 parts, so a 9th-gen or Xeon E-22xx chip won't be recognised until the firmware is current. HP publishes no numeric thermal limit, but validated parts reach 95 W (for example Core i9-9900K, Core i7-9700K and Xeon E-2286G), which tells you the board and cooler are built for roughly that class of chip. Make sure your unit has the higher-performance heatsink before fitting one of these. Also note that HP states Core i-series models support Windows 10 only.

A CPU swap can change your memory options: moving to a Xeon E, Core i3 or Pentium unlocks ECC memory support, while Core i5/i7/i9 builds are non-ECC only.

Buying tip: check the cooler first — a hot chip in a case with the basic heatsink is an expensive mistake. And if you're moving to a 9th-gen CPU, plan the BIOS update into your timeline: it has to happen while the old CPU is still installed.

Buying tips

• LGA 1151, 8th/9th-gen Core, Pentium Gold or Xeon E-2100/E-2200
• Update the BIOS before fitting a 9th-gen or Xeon E-22xx CPU
• Confirm the higher-performance heatsink before buying a 95 W chip
• A Xeon E, i3 or Pentium swap enables ECC memory

How to upgrade

Before you start

• Back up anything important before touching the hardware.
• Shut down the computer and unplug the power cord and all cables.
• Ground yourself to discharge static — an anti-static strap or a bare-metal part of the case works.
• For the CPU change, update the BIOS first, while the old processor is still installed.
• Open the case. HP's owner's manual shows the exact disassembly for your chassis, so keep it to hand.
• Install the new part (memory in matched pairs, M.2 drive 110 mm or shorter).
• Close the case, reconnect the cables and power on.
• Check that the BIOS or firmware sees the new part before you boot into the operating system.

Steps

1. General installation outline
   Back up first, then power down and unplug the machine. Ground yourself against static, open the case, install the part, close the case and reconnect everything. Finally, start the computer and confirm the BIOS or firmware reports the new memory, drive or processor correctly.
2. Device-specific details worth knowing
   Memory is installed as matched pairs in the paired slots (DIMM1 with 3, DIMM2 with 4). M.2 storage drives must be 110 mm or shorter. A BIOS update is required before fitting a 9th-gen or Xeon E-22xx processor. For step-by-step disassembly, refer to HP's owner's manual for the Z2 Tower G4.

Good to know

• Regional CPU lists differ from the worldwide specification, and availability of any given processor varies by region and configuration.
• HP's documents don't publish a maximum drive capacity per bay — physically fitting is not the same as being validated.
• HP supports only HP-qualified PCIe cards in the Gen3 x16 slot for warranty purposes; third-party cards generally work but are unsupported.

Frequently asked questions

How much RAM can the HP Z2 G4 Tower take?

128 GB in total, using four 32 GB DDR4 UDIMMs. HP validated that configuration even though Intel's published spec for these CPUs tops out at 64 GB, so third-party 32 GB DIMMs aren't guaranteed to work. The Z2 G4 SFF, by contrast, has 2 DIMM slots and a 64 GB maximum.

Does the Z2 G4 Tower support ECC memory?

It depends on the processor. Xeon E-2100/E-2200, Core i3 and Pentium chips accept ECC or non-ECC unbuffered memory; Core i5/i7/i9 systems accept non-ECC only. The two types can never be mixed in one machine. Swapping to a Xeon E, i3 or Pentium is the way to unlock ECC.

Does it support NVMe SSDs?

Yes. There are 2 M.2 slots running PCIe Gen3 x4 NVMe, and drives up to 110 mm long fit (2242, 2260, 2280, 22110). M.2 SATA support isn't clearly documented in HP's material, so verify compatibility before buying an M.2 SATA drive.

How many hard drives or SATA SSDs can I install?

There are 4 SATA 6 Gb/s ports and two internal 3.5-inch bays, plus two external half-height 5.25-inch bays. If the optical drive is fitted it uses one port, so a third or fourth SATA drive needs a 5.25-to-3.5-inch carrier. More than four SATA drives means adding a PCIe host bus adapter.

Do I need a BIOS update before changing the CPU?

Yes, if you're installing a 9th-generation Core or a Xeon E-22xx processor. Early BIOS revisions only recognise 8th-gen and Xeon E-2100 parts, so update the firmware first, while the old processor is still in place.

Can I put a faster 95 W processor in my Z2 G4 Tower?

Validated parts include 95 W models such as the Core i9-9900K, Core i7-9700K and Xeon E-2286G, but HP shipped different coolers depending on the original configuration. Check that your unit has the higher-performance heatsink before fitting one. Note too that HP states Core i-series models support Windows 10 only.

Official documents and references

• HP Z2 Tower G4 Workstation QuickSpecs
  Full CPU lineup, memory rules and M.2/HP Z Turbo Drive options
• PDF HP Z2 Tower G4 Workstation Maintenance and Service Guide (PDF)
  Official service manual — disassembly, parts and operating system notes
• HP Z2 Tower G4 Workstation Owner's Manual
  Expansion slot layout and configuration limits
• PDF HP Z2 Tower G4 technical specifications (PDF, Japanese)
  DIMM slot pairing and SATA port details
• PDF HP Z2 Tower G4 datasheet (PDF, Japanese)
  Regional CPU and configuration list — narrower than the worldwide list
• PDF HP Z2 G4 configuration guide (Avid)
  Third-party config reference listing top CPU options