Using a mac mini with a docking station for dual monitors

Mac mini (2018) - Technical Specifications - Apple Support

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Support for the following combination of maximum concurrent display setups:

Up to three displays:

• • Two displays with 4096-by-2304 resolution at 60Hz connected via Thunderbolt 3 plus one display with 4096-by-2160 resolution at 60Hz connected via HDMI 2.0

Up to two displays:

• • One display with 5120-by-2880 resolution at 60Hz connected via Thunderbolt 3 plus one display with 4096-by-2160 resolution at 60Hz connected via HDMI 2.0

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So it sounds like your Mac should be able to drive two displays with resolutions of up to 4K @ 60 Hz over USB-C or Thunderbolt … and I would expect that that with many Thunderbolt docks, you would be able to drive both of them through a single Thunderbolt dock.

The issue is possibly related to the fact that the Dell WD19TB Thunderbolt Docking station has four video outputs.

• Two DisplayPort 1.4 outputs
• One HDMI 2.0b output
• A USB-C port that carries a DisplayPort signal

Macs do not support DisplayPort MST daisy-chaining, and my impression is that they normally support attaching at most one display via a plain USB-C dock, or two displays via a Thunderbolt dock.

I don't know what a Mac would make of the four possible display outputs on this dock – if there are certain pairs of outputs that could get separate video signals (for extended desktop mode), and if there are other pairs of outputs that might always get the same signal (because the Mac was only providing one, and the dock was replicating it).

I'm just guessing that it is likely to be something like that.

The difference between Thunderbolt 3 and Thunderbolt 4:

Please refer to this chart:

You might want to explore dual Thunderbolt controllers (that means you have to use TWO thunderbolt cables to connect to the dock) for this Thunderbolt 3 (2018 Mac Mini).

1 single TB connection docking station will only output 1 display on 2018's Mac Mini.

There are few docking stations has TWO Thunderbolt Controllers -- BUT specs are all over the places (some only works with M series Macs).

Best

rparmet wrote:

Is this possible with a different docking station?

Possibly experimenting with using different combinations of two video outputs from the Dell Thunderbolt dock will resolve the problem.

With regards to other Thunderbolt docking stations, you could look at the ones offered by Other World Computing, SonnetTech, and CalDigit . I do not have experience with any of these docks, but all three of these companies have been in the business of selling Thunderbolt equipment to Mac users for a long time.