Apple imposed limitations in its M1 series of Macs about how
many external displays could be attached. It's just one for most
models; a Mac mini lacks an integral display, and can support two.
DisplayLink technology offers a way to add more displays for M1
Macs by effectively encapsulating video over USB 3. This works with
M1 Macs as well as Intel Macs that lack all the output ports you
want, PCs, and other devices.
Synaptics, the creator of DisplayLink, licenses their technology
to manufacturers. I tested the only 4K UHD adapter that appears to
be in stock anywhere right now: the StarTech.com USB 3.0 to HDMI
Adapter, which is DisplayLink certified. It supports resolutions up
to 3840 by 2160 pixels and a display refresh rate up to 60
Configuration of the
provided display is effectively nil. You can opt to load the driver
on demand instead of at restart.
The driver installs without requiring a restart. When necessary,
it prompts you to grant permissions via the Security Privacy
preference pane's Privacy tab to Screen Recording, part of how it
works with macOS to pretend to be another display.
I tested the most recent DisplayLink driver with an M1 Mac mini
running macOS 11.6 Big Sur, with two displays already attached via
HDMI and a USB-C-to-HDMI adapter; and with an M1 MacBook Air with
Monterey installed, with one external display plugged in via a
I plugged in the StarLink adapter directly to a Type-A port on a
USB-C dock and tested it through a Type-A-to-USB-C adapter as well.
In every configuration, the software and hardware functioned
exactly as hoped. Both Macs I tested with recognized the monitor
connected via the StarLink adapter immediately.
display appears at right just like the internal display of an M1
MacBook (left) and an external 4K monitor (center), shown in the
Monterey public beta.
A DisplayLink-attached monitor appears in the Displays
preference pane exactly like any screen attached through an
Apple-provided pathway. You can re-arrange it, perform color
calibration, and make it the main display that holds the menu bar.
Everything simply works.
I tested dragging a Safari window playing a video in YouTube
across three displays with no stutters or hiccups. The video
continued to play as smoothly moving it back and forth from the
DisplayLink-connected monitor as it did between the two
If you're an M1 Mac owner feeling stymied by a lack of monitors
or own an Intel Mac with not enough built-in support, the
StarLink.com DisplayLink 4K/60Hz adapter may be worth the price to
expand your desktop.