USB Adapter Claims Quadruple Support for Mac M2 and M1 Monitors

The Plugable dock maker says it has found a way to increase the number of external monitors supported by M1 and M2-based Macs. While Apple says Macs with these chips can support one to two external monitors, Redmond, Washington-based Plugable says the new USB-to-HDMI adapter supports up to four monitors.

According to Apple, a Mac Mini with an Apple M1 processor can support up to two monitors. However, all other M1 and M2 based devices are limited to one external display.

To address this limitation, Plugable on Tuesday released a USB-C or USB 3.0 to Quad HDMI adapter (USBC-768H4), saying it supports up to four monitors via HDMI, including those for M1 and M2 Macs. The adapter requires you to be running Windows 10 or macOS 11 and later.

The Plugable announcement says that the adapter can increase support for M1 and M2 monitors because it does not depend on alternate mode. Instead, the adapter uses a chipset from Silicon Motion, known for making NAND flash controllers for solid state drives, as well as a software driver.

For Windows users, the driver is updated automatically, according to Plugable. In the meantime, Mac users need to download the Silicon Motion InstantView app. According to Silicon Motion, the app supports extended and mirroring on macOS.

“When the docking station is connected every time, it automatically allows the monitor to display the laptop screen without any user intervention,”says the Silicon Motion InstantView website. Other products using InstantView include docks from Accell and Wavlink.

Of course, there are caveats regarding the Plugable adapter.

First, Apple does not officially support this product, and its support page for connecting monitors to Macs notes that “using docking stations or daisy chain devices does not increase the number of displays you can connect”to Macs M1 or M2. So we wouldn’t be surprised if you run into any road bumps while driving four monitors on one of these Macs.

And don’t expect to create a pixel paradise with high resolution screens. Each of the four monitors connected via HDMI is limited to a resolution of 1920×1080 at a refresh rate of 60Hz. Even when using all ports, Mac users will be limited to the number of pixels equal to one 4K screen.

However, Windows users get a little more. By adding two adapters to the Quad HDMI adapter, Plugable says you can add up to eight monitors to your Windows PC.

We’ve seen products that claim to support adding a 4K monitor as well as another display to the M1 Mac, including the Anker 563 USB-C Dock and Docks from Plugable. But 4K will likely be limited to 30Hz.

It’s also worth noting that the Plugable Dock does not support DisplayLink. And the vendor drops expectations by claiming the adapter isn’t for “gaming, graphics, or design work,”without going into the details of what that means.

Finally, you won’t be able to play HDCP-protected content with the adapter, Plugable says.

Despite its limitations, the Plugable adapter still claims to be an easy way to increase the number of displays, addressing basic multi-monitor setups and especially M1 and M2 users. The Quad HDMI adapter costs $120.