Duet Display, the $9.99 app that turns a tethered iPad or iPhone into an extra display for your Mac or Windows PC, is now more capable than ever thanks to performance improvements and new split-screen multitasking support. Available to download now from the Apple App store, version 1.2 lets you dedicate any iPad or iPhone display for use as a second monitor. Or you can allocate two-thirds of the display for Mac apps if you own an iPad Air 2 or iPad Pro, while the other third can be used for your favorite split-screen iOS apps.
I’ve been using Duet daily for the past year. In fact, I’m using the new version right now on a four-year-old iPad connected to the latest MacBook (yes, the one with the single USB Type-C jack). It’s a very impressive, and very portable dual-display setup with zero lag, unlike traditional screen-sharing apps that rely upon Wi-Fi. I can even watch 1080p videos at 60fps over Duet. The setup does, however, require that the iPad or iPhone be tethered to the Mac or PC via a 30-pin or Lightning cable.
We also tested version 1.2 running on an iPad Pro. Its 12.9-inch display makes the Duet setup feel like a legitimate monitor, not a miniature display running on a 9.7-inch tablet. Selecting the "iPad Pro" resolution generates a lot of real estate but it also leads to a lot of squinting. Selecting the regular resolution worked just fine and still felt spacious. There's rudimentary Apple Pencil support too, but it's not very useful and doesn't yet recognize pressure.
$9.99 spent on Duet will be money well spent
Mind you, the Duet experience is close to, but not exactly like using a dedicated display. For example, there's the occasional graphical weirdness (app flicker when dragging windows from one display to the other) when running at the most conservative, energy-efficient settings. And twice over the last few days of testing we’ve had to quit the frozen app and relaunch to clear up connectivity issues. However, compared to previous versions of Duet, 1.2 feels much more stable and my MacBook CPU isn’t nearly as taxed (the release notes claim a 50 percent reduction of Mac CPU usage).
Bottom line: if you own an iPad and crave a portable dual-display setup for your Mac or PC, then the $9.99 spent on Duet will be money well spent.