Mac mini M2 connecting 2 displays via a Thunderbolt hub/dock

If those Dell 4K monitors have both DisplayPort and HDMI inputs, would it make sense to attach one to the M2 Mac Mini via HDMI, and the other via USB-C (DisplayPort)?

The M2 Mac Mini supports up to two external displays.

• One display with up to 6K resolution at 60Hz over Thunderbolt and one display with up to 5K resolution at 60Hz over Thunderbolt or 4K resolution at 60Hz over HDMI

They can both be Thunderbolt or DisplayPort displays (an upgrade over the capabilities of the M1 Mac Mini). However, the option to attach one of your two displays via HDMI is still there.

Mac mini (2023) - Technical Specifications

Unless there's some disadvantage to HDMI that you're trying to avoid, doing things that way would keep you from having to use both multi-purpose USB4 (TB) ports just to attach your displays.

I'll make an educated guess. (For a definitive answer, you'll have to ask Apple.)

First, let's distinguish between USB-C (DisplayPort ALT mode) displays (which don't need Thunderbolt input), and Thunderbolt displays (which do). DIsplays that actually connect via Thunderbolt are pretty rare, although you will find many descriptions of USB-C (DisplayPort ALT mode) cables and adapters that mention Thunderbolt. Usually this is because the vendor is trying to emphasize that the product will work with Macs - not because the products rely (or should rely) on Thunderbolt. Vendors don't always make this clear (and I suspect that the marketing types who write the advertising copy may simply not know!).

I don't know if Apple Silicon Macs support daisy-chaining DIsplayPort displays. There is an optional feature in the DisplayPort specification that allows for this, but Macs never supported that feature in the days of Thunderbolt 1/2 (which had Mini DisplayPort connectors and could pretend to be Mini DisplayPorts). They still may not support it. That's an issue on which Apple's technical specifications and user support documents appear to be silent.

With respect to Thunderbolt displays, I believe that Thunderbolt can carry two encapsulated DisplayPort sessions. If you had two Thunderbolt monitors, and either of them had a resolution of 5K or 6K, it would need both sessions for itself. In that scenario, you'd need to attach the Thunderbolt monitors to different ports. I don't know whether a Thunderbolt hub (which splits one chain into several) could help you with that resource contention issue.

If both of your monitors were Thunderbolt monitors and had resolutions of UHD 4K (3840x2160 pixels) or less … and at least one of them had two Thunderbolt ports (to allow daisy-chaining), I think you could daisy-chain them. Each would consume one of the two DisplayPort sessions within the Thunderbolt signal.

Someone else can correct me, if I'm wrong, but this is the impression I've formed from my reading.

I followed the link that you provided to OWC's description of their Thunderbolt hub. If you take a look at the first illustration, it shows a link from one of the downstream hub ports going to two 4K monitors or one 5K/6K/8K one.

https://www.owc.com/solutions/thunderbolt-hub

https://eshop.macsales.com/tech_center/manuals/owc-thunderbolt-hub-user-guide.pdf

This seems to jibe with my description of how many Thunderbolt displays you can attach to one Thunderbolt port.

If you have questions about whether you can plug two "plain" USB-C displays (with resolutions of up to 4K) into the OWC Thunderbolt Hub, and have that work with a M2 Mac Mini, you might want to contact OWC Technical Support.

Julian Wright wrote:

Thank you.

I'm hoping to connect 2 x 4K Dell monitors (which have DisplayPort and HDMI connections - no actual Thunderbolt ports) to the Thunderbolt hub. Currently I have one monitor connected via Thunderbolt ➜ DP through the Thunderbolt hub, and one monitor connected via HDMI ➜ HDMI.

Thunderbolt (M2 Mini) -> OWC Thunderbolt Hub -> USB-C(DP)-to-DP -> monitor, I suspect

The manual for your OWC hub says that "a display connected via a USB-C device adapter" can be added to the end of a device chain. The following DISPLAY NOTES seem to imply that you can plug a second USB-C adapter into another port on the Thunderbolt hub.

They don't say that you can daisy-chain two DisplayPort displays off the same downstream hub port … and that makes me think that the Apple Silicon Macs probably don't support DisplayPort daisy-chaining.

However, it sounds like you can have up to five devices attached to the three ports on the OWC Thunderbolt hub (with two of the devices being USB-C adapters plugged directly into separate hub ports, or the ends of separate Thunderbolt device chains).

Possibly the only 100% way to find out is to buy another cable and try!

One nice thing about USB-C to DisplayPort cables is that they don't cost very much.

Good luck, and let us know whether it works (or not).