Somewhat confused by the Thunderbolt/Mini DisplayPort compatibility rules, and the apple store people were unhelpful, so I ask here (maybe I should ask here first :) Hopefully we can come to a complete compatibility matrix.

I have a 27" iMac from December 2010 ("old imac") and another 27" iMac ("new imac") from July 2011. The first is MDP and the second is TB. I also have a MBP from July 2010 (which is MDP) and a MBA from August 2011. I would like to make a unified setup.

What devices can be used as monitors for other devices? For example, I know that I can use an MDP cable to connect the MBP to the old imac.

3 Answers 3


The following options will work for you:

  • old iMac as a display for MBP, MBA and new iMac. Use a mDP cable.
  • new iMac as a display for MBA. Use a TB cable.
  • 1
    Can I use the mDP cable to connect the MBA to the new iMac?
    – Foo Bah
    Aug 24, 2011 at 19:21
  • 1
    No. You'll need a TB cable for that.
    – robmathers
    Aug 24, 2011 at 19:35

From what I understand, the devices need to have the same connector technology, i.e. a Mini DisplayPort device will talk to another one, and a Thunderbolt device will talk to another one, but you can't cross connector technologies—no Mini DisplayPort on one side, Thunderbolt on the other.


The matrix is simple - matched icons on the ports is a winning combination.

Video in requires matching cable and port on the sending mac. (If all don't match, it won't work.)

Display mirroring (where an iMac can receive video input) only works thunderbolt to thunderbolt or displayport to displayport

The backwards compatibility between the formats only works when a displayport monitor is connected to a thunderbolt mac.

  • I have a quick question about your answer. With the last sentence, does that mean using a brand new MBP (with TB) can use a 2010 iMac with DisplayPort?
    – jmlumpkin
    Oct 26, 2012 at 15:08
  • @jmlumpkin Yes - as long as any iMac runs in target video mode, you can then plug it in to any DisplayPort or Thunderbolt Mac just as you could use any TB/DP monitor with the same effect.
    – bmike
    Oct 26, 2012 at 15:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .