With Thunderbolt-capable iMacs – the Mid 2011 models and up – Target Display Mode will only work with other Thunderbolt-capable devices. Even though Thunderbolt also handled DisplayPort video, the new complexities of the Thunderbolt controller meant that Target Display Mode would be far more restrictive.

Now, users could not only add displays to their Mac, they could also daisy chain all manner of hard drives, storage arrays, card readers, and other external devices.

Thunderbolt changed all of that by bringing data I/O into the mix. Prior to Thunderbolt, the iMac’s Mini DisplayPort connection was used exclusively for video and audio. With the introduction of Thunderbolt on the 2011 iMacs, however, things suddenly became far more complicated. Target Display Mode quickly became a much-loved feature of the 27-inch 2009 iMac, and it persisted with the 27-inch 2010 model. With the proper adapters, DisplayPort can accept DVI and HDMI sources, meaning that practically any computer or video device using these standards could work with TDM, including PCs, game consoles, and even other Macs. But unlike a standalone monitor, users were traditionally unable to share the display with another computer or device, leaving the iMac’s large and high quality screen dedicated only to the Mac within.Īpple sought to address this shortcoming in 2009 with the release of a new feature called “Target Display Mode.” Available initially only on the 27-inch Late 2009 iMac, Target Display Mode (TDM) allowed users to plug a compatible device into their iMac’s Mini DisplayPort and gain exclusive use of the iMac’s display. A benefit of Apple’s iMac is that users get a monitor and computer in one relatively small package.

Late 2013 imac review