Multiple Displays

27-inch iMac supports up to three displays

Apple's new big-screen 27-inch iMac, comes with two Thunderbolt ports for both high-speed input/output and Mini DisplayPort support for additional monitors. The inclusion of two Thunderbolt ports means the iMac can support three displays, when combined with the 27-inch screen on the all-in-one machine.

Engadget put the new feature to the test, hooking two 30-inch Dell displays up to the two Thunderbolt ports on the 27-inch iMac. The end result was a total of 11,878,400 pixels spanning three displays, which can be seen below.

But if you are a glutton for extra screen space, the 27-inch iMac delivers much more than just its own monitor. Thanks to two Thunderbolt ports with DisplayPort support, you can plug in two extra monitors with no additional equipment or drivers needed (beyond Mini DisplayPort adapters). After years of odd quirks and frequent updates with DisplayLink USB drivers, this is a very welcome addition.

And the iMac has the power to make multi-display workflows very smooth, even in cases where you might require a lot of muscle. For instance, just today I was running Civilization V, while also preparing this post, running about 20 tabs in Chrome, editing a few documents in Photoshop, and controlling my HTPC Mac Mini via Apple’s Screen Sharing app. Not to mention iTunes, Twitter, Mail and the Mac App Store were all open as well, and all of the above were spread across three monitors (the iMac’s own monitor and two Dells, a 20-inch and a 23-inch). Animation in the windowed Civ V remained smooth, and I experienced nary a stutter in my interaction with other open apps.

Users who want to use more than one external monitor with their Mac have so far been fairly limited in their options. You can use a USB-to-DVI or VGA solution, as I’ve mentioned before, or you can use a wireless solution such as Air Display, but both solutions offer downsides (USB video adapters don’t support things like 3D acceleration and wireless solutions inevitably have some degree of lag) that native wired DisplayPort output does not.

Now, using two Mini DisplayPort adapters plugged in to the 27-inch iMacs Thunderbolt ports, users can simultaneously output to two monitors in addition to the main built-in screen of the iMac. It won’t necessarily clog up your Thunderbolt ports, either, since the tech supports daisy-chaining. That means you should be able to connect to Thunderbolt-compatible storage and then on to a display after that, too, without any loss of quality.

Having the ability to output to two additional monitors built-in makes the 27-inch iMac a very attractive machine for audio/visual professionals, and also for pretty much anyone who values more screen real estate in their work. Before today, you could spend hundreds of dollars trying to add-on the ability to your Mac using third-party software and hardware. This could very well be the tipping point for many who were considering an upgrade, but were unsure about whether or not they really needed to do so.