HP's exact 5Z5B5EA sheet lists both dock families, so the useful decision is connection type and desk layout rather than connector guessing.
Choose screen count and see dock options
Laptop · Reviewed 8 September 2026 · Documentation-based, not hands-on testing
For HP EliteBook 840 G8, choose HP USB-C Dock G5 when its rear HDMI and DisplayPort layout is enough and you want a conventional USB-C deployment. Choose HP Thunderbolt Dock 120W G4 (4J0A2AA) when the notebook's Thunderbolt 4 path and the G4's downstream connectivity are the reason to dock. HP's exact 5Z5B5EA specification sheet lists both accessories. It does not turn either listing into a promise for every display combination, and a different 840 G8 SKU still needs its configuration checked.
HP lists the G5 in the reviewed EliteBook 840 G8 5Z5B5EA sheet and documents rear HDMI and DisplayPort outputs with up to 100 W host power.
Check first: Two 4K60 displays require the right host DisplayPort capability and dock mode. The exact SKU sheet does not state every combined monitor mode.
The same exact-model sheet lists this Thunderbolt 4 dock package, making it the documented higher-bandwidth HP option for the reviewed SKU.
Check first: The 120 W supply rating is not the power delivered to the notebook. Confirm the exact package, firmware, monitor outputs and negotiated charge.
The notebook's Thunderbolt 4 connection is the clean way to separate a host or monitor problem from the dock path.
Check first: Use a known video-capable cable or adapter. A direct result does not establish an unlisted dock or the same mode through MST.
Still unknown: The reviewed sheet covers SKU 5Z5B5EA; memory, display panel, regional SKU and firmware can differ. HP does not establish every mixed-resolution, refresh-rate, HDR, adapter, cable, security-policy or sleep/wake combination for both docks in that sheet, and no physical 840 G8 setup was tested here.
Compare documented options · Check screens and power
Applies to HP EliteBook 840 G8, with 5Z5B5EA as the exact reviewed SKU. Do not transfer the result to 840 G7, G9, Aero G8 or x360 830 G8. Sources reviewed 19 September 2026. Manufacturer documentation is not a Connect Your Dock hardware test.
Manufacturer guidance
4K and three-screen modes depend on the host’s DisplayPort capability and dock display mode.
HP names the USB-C Dock G5 in this model’s linked document. Check your exact configuration, current firmware and combined display modes; the listing is not a complete desk test.
Manufacturer guidance. This is a shortlist, not a test of your complete desk.
Manufacturer guidance
HP lists Thunderbolt Dock 120W G4 / 4J0A2AA in the reviewed 840 G8 SKU sheet. Up to 100 W host delivery is distinct from the 120 W supply. Check the exact screen modes.
Manufacturer guidance. This is a shortlist, not a test of your complete desk.
Check model-specific limits
The exact model’s published video interface meets the dock’s host requirements. This is an inference from separate specifications, not a manufacturer-approved pair or a hardware test. Confirm screen modes, charging, firmware and peripherals.
Check model-specific limits. This is a shortlist, not a test of your complete desk.
Check model-specific limits
The exact model’s published video interface meets the dock’s host requirements. This is an inference from separate specifications, not a manufacturer-approved pair or a hardware test. Confirm screen modes, charging, firmware and peripherals.
Check model-specific limits. This is a shortlist, not a test of your complete desk.
Check model-specific limits
Two revisions share this name: black V1 (Aug 2022–Aug 2024) and silver V2 (serial 4157+, Aug 2024 onward). Identify yours before using port guidance.
The exact model’s published video interface meets the dock’s host requirements. This is an inference from separate specifications, not a manufacturer-approved pair or a hardware test. Confirm screen modes, charging, firmware and peripherals.
Check model-specific limits. This is a shortlist, not a test of your complete desk.
| Check | For this setup |
|---|---|
| Computer cable | The attached G5 USB-C cable goes to the laptop’s video-capable USB-C port. |
| Screen cables | Use rear HDMI or DisplayPort. The front USB-C socket is for data and 15 W accessory power, not a monitor. |
| Two Full HD screens | Listed in every G5 bandwidth column, assuming the host supports the display count. Confirm the exact laptop configuration and OS. |
| Two 4K60 screens | Require DP 1.3/1.4 in high-resolution mode, or DP 1.4 with DSC in the default mode. A USB-C socket alone establishes neither. |
| Three 4K60 screens | Only listed with DP 1.4 DSC in high-resolution mode; all three rear video outputs are used. |
| Power | Up to 100 W to supported HP hosts. A workstation requiring more needs separate supported power. |
See the cable arrangement and troubleshooting steps
HP lists the G5 and Thunderbolt G4 in the reviewed 840 G8 SKU sheet. Confirm your configuration and display modes.
Documented direct connection: Thunderbolt 4 USB-C video / charging port.
Check one screen without a dockRead the relevant setup guide · Fix a connection problem
