The catch
Plugable TBT-UDM
There is no direct DisplayPort and Ethernet is only Gigabit. The total native display limit is two, and some hosts have lower limits.
Side by side
TBT-UDM vs TBT4-UDZ from Plugable: A Thunderbolt drive suits TBT-UDM, more screen routes suit UDZ
Quick verdict
A downstream Thunderbolt port is what the TBT-UDM retains, and the TBT4-UDZ counters with more fixed display sockets and 2.5GbE. Two compatible HDMI screens and a Thunderbolt drive call for the TBT-UDM. Direct DisplayPort connections, or a supported Windows multi-screen setup, are reasons to take the UDZ over Thunderbolt storage at the dock. Four video sockets on the UDZ do not give a Mac four native displays, and two Mac screens have to sit on different output groups.
Before you buy
Why, and what it costs you
The spare Thunderbolt port only becomes useful once the monitor plan is settled
Two HDMI monitors let TBT-UDM keep its downstream TB4 port free for a Thunderbolt drive, which makes a clean work-and-photo-editing layout. If one monitor is DisplayPort-only, that changes, because a compatible TB-to-DP cable then uses the same port and the drive loses its direct dock connection. UDZ takes the DP monitor directly but has no downstream TB port at all. The right answer therefore depends on the real screen inputs and on whether the drive has to live on the dock. If both screens accept HDMI, TBT-UDM is the easier TB-storage choice. If the drive can connect straight to the laptop and the DisplayPort cables should stay, UDZ may fit better.
Where this comes from
Connector occupancy for two example screen types and a TB-only drive. TBT-UDM has one downstream TB branch against zero on UDZ. It does not assert that dual-protocol drives cannot use USB or that every video adapter supports every mode.
The catch
Plugable TBT4-UDZ
There is no downstream Thunderbolt port. Dual displays on a Mac need one socket from each group, and four screen outputs still do not add up to four Mac display streams.
Plugable TBT-UDM
- Why pick it
- You plan to keep two HDMI monitors and a Thunderbolt drive connected to a single supported laptop setup.
- Gigabit networking is all you need, and 96W of certified host power suits the laptop.
- The catch
- There is no direct DisplayPort and Ethernet is only Gigabit. The total native display limit is two, and some hosts have lower limits.
Plugable TBT4-UDZ
- Why pick it
- At least one screen needs a direct DisplayPort connection, or a supported Windows host can make use of the extra MST display routes.
- A 2.5GbE local network is in place and matters to you, and no downstream Thunderbolt device has to attach at the dock.
- The catch
- There is no downstream Thunderbolt port. Dual displays on a Mac need one socket from each group, and four screen outputs still do not add up to four Mac display streams.
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What this page compares
TBT-UDM vs TBT4-UDZ for a setup with HDMI and DisplayPort monitors, a Thunderbolt SSD and a home NAS. See which ports are still usable once the screens are plugged in.
These Plugable Thunderbolt 4 desktop docks both have native video and charging near 100W. Someone with two existing monitors can reasonably choose either, but the larger socket count on UDZ takes away the downstream TB option.
Which one fits
Pick the situations that sound like you
The dock keeps two HDMI screens and a TB-only drive
One TB port stays on TBT-UDM, and UDZ has none.
- Plugable TBT-UDM
- Better fit
- Plugable TBT4-UDZ
- Not suitable
Both screens ought to keep using the DisplayPort cables they have
Direct DP sockets are on UDZ. For a compatible Mac, check the different groups.
- Plugable TBT-UDM
- Caution
- Plugable TBT4-UDZ
- Better fit
More than two displays are needed from a verified Windows host
Supported MST routes are usable on UDZ. The exact host and display modes are essential.
- Plugable TBT-UDM
- Not suitable
- Plugable TBT4-UDZ
- Better fit
Two native external screens are needed on a basic M1 or M2 Mac
The host ceiling is not removed by either native dock.
- Plugable TBT-UDM
- Not suitable
- Plugable TBT4-UDZ
- Not suitable
In practice
Differences you will notice
The spare Thunderbolt port only becomes useful once the monitor plan is settled
Two HDMI monitors let TBT-UDM keep its downstream TB4 port free for a Thunderbolt drive, which makes a clean work-and-photo-editing layout. If one monitor is DisplayPort-only, that changes, because a compatible TB-to-DP cable then uses the same port and the drive loses its direct dock connection. UDZ takes the DP monitor directly but has no downstream TB port at all. The right answer therefore depends on the real screen inputs and on whether the drive has to live on the dock. If both screens accept HDMI, TBT-UDM is the easier TB-storage choice. If the drive can connect straight to the laptop and the DisplayPort cables should stay, UDZ may fit better.
How we worked this out
Connector occupancy for two example screen types and a TB-only drive. TBT-UDM has one downstream TB branch against zero on UDZ. It does not assert that dual-protocol drives cannot use USB or that every video adapter supports every mode.
Having four sockets does not give a shared Mac desk four useful screens
The extra video sockets on UDZ are attractive when a Windows work machine drives several displays and a personal Mac uses the same desk later. The Windows MST capability does not carry over unchanged to macOS. A supported two-screen Mac setup has to take one output from each group, and a basic M1 or M2 laptop still has its native one-screen limit. Labeling the Mac connections you intend to use can save you from changing cables again and again when you swap computers. If both computers only need two HDMI screens, TBT-UDM already covers that simpler plan with a supported host. Pick UDZ for a verified Windows multi-screen need or for direct DP convenience, and not for a Mac display upgrade you only assume.
How we worked this out
UDZ display-group and platform limits, set against alternating Windows and Mac use. There is no universal four-screen Windows promise. Host model, resolution, GPU and cable remain gating facts.
A faster NAS and a Thunderbolt drive push the decision different ways
A household that uses both network photo storage and a portable Thunderbolt drive has two distinct data routes. UDZ provides 2.5GbE, which helps only when the NAS path can exceed Gigabit, but it gives the drive no TB port. TBT-UDM has a TB port and only Gigabit Ethernet. Before choosing, decide which transfer is the recurring delay and whether a separate laptop connection is acceptable for the other device. On a 1GbE switch, the network link advantage of UDZ disappears and the free TB branch becomes more useful. On a ready 2.5GbE network, with the drive already attached directly to the laptop, UDZ can fit the routine. Neither dock wins on both connections by total port count.
How we worked this out
Independent Ethernet and TB paths, set against local backup and portable-drive use. In the stated slower-switch example, min(2.5, 1)=min(1, 1)=1Gb/s is the switch-link ceiling. No measured transfer-time claim is made.
Option A
Plugable, TBT-UDM
Plugable TBT-UDM
You plan to keep two HDMI monitors and a Thunderbolt drive connected to a single supported laptop setup.
- Best for
- You plan to keep two HDMI monitors and a Thunderbolt drive connected to a single supported laptop setup.
Facts we checked
- Fixed video outputs: Two HDMI
- Downstream Thunderbolt: One port
- Two-screen Mac layout: Two native displays across HDMI and TB, if host supports them
- Network link: Gigabit Ethernet
Option B
Plugable, TBT4-UDZ
Plugable TBT4-UDZ
At least one screen needs a direct DisplayPort connection, or a supported Windows host can make use of the extra MST display routes.
- Best for
- At least one screen needs a direct DisplayPort connection, or a supported Windows host can make use of the extra MST display routes.
Facts we checked
- Fixed video outputs: Two HDMI and two DisplayPort, in two groups
- Downstream Thunderbolt: None
- Two-screen Mac layout: One display from each output group, if host supports both
- Network link: 2.5GbE
Spec by spec
Where they really differ
| Spec | Plugable TBT-UDM | Plugable TBT4-UDZ | In practice |
|---|---|---|---|
| Fixed video outputs | Two HDMI | Two HDMI and two DisplayPort, in two groups | DP cables can be reused on UDZ, though grouping and host support limit what runs at the same time. |
| Downstream Thunderbolt | One port | None | A storage plan can overturn a decision that was made on monitor socket count. |
| Two-screen Mac layout | Two native displays across HDMI and TB, if host supports them | One display from each output group, if host supports both | The Mac's own ceiling stays in place. Two sockets side by side may not be independent paths on a Mac. |
| Network link | Gigabit Ethernet | 2.5GbE | A 1GbE switch caps both, though a faster NAS path can favor UDZ. |
| Certified host power | 96W | 98W | Do not expect a meaningful change in charging time from the 2W difference. |
Trade-offs
What each pick costs you
With Plugable TBT-UDM
- A compatible TB-to-DP connection is needed for a DisplayPort-only monitor, and it uses the sole downstream TB port.
With Plugable TBT4-UDZ
- For a TB-only drive, you need a separate suitable host port or a verified expansion plan. Ordinary USB-C data is no substitute.
Change of plan
When the answer changes
Thunderbolt storage still has to sit behind the two HDMI screens
Go with Plugable TBT-UDM. The required downstream connection is kept by TBT-UDM.
The missing job is direct DP or verified Windows screen expansion
Go with Plugable TBT4-UDZ. Those paths come with UDZ, subject to platform and grouping limits.
Decision guide
Before you buy
Room for more screens is what you want, with no surprise later that the drive or network you use for personal projects needs another adapter.
What this page can’t tell you
- Nothing here reports a measured difference in file speed or charging time. Display limits on Mac and Windows differ and cannot be swapped for one another. Neither dock works as a hardware KVM or does away with safe-eject requirements.
By the numbers
What the data shows
What we found across the docking stations we compare, plus the checked facts behind each finding.
Show the facts and the math
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| Plugable TBT-UDM |
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| Plugable TBT4-UDZ |
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Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
Plugable TBT-UDM
You plan to keep two HDMI monitors and a Thunderbolt drive connected to a single supported laptop setup.
Gigabit networking is all you need, and 96W of certified host power suits the laptop.
See price & reviews on AmazonPlugable TBT4-UDZ
At least one screen needs a direct DisplayPort connection, or a supported Windows host can make use of the extra MST display routes.
A 2.5GbE local network is in place and matters to you, and no downstream Thunderbolt device has to attach at the dock.
See price & reviews on AmazonEach link opens in a new tab.
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