I have a mid-2014 MBP retina with the Intel Iris Pro 1536 MB GPU running Yosemite.

Current setup:

  • 1x 27" Thunderbolt Display
  • 1x 27" Cinema Display

I went to connect another non-Apple monitor to my MBP via HDMI or also the Thunderbolt port on the back of my Thunderbolt display however the 3rd external monitor does not detect a single. Searching around I find out that there is a limit to the number of displays a MBP can run although I see some people are able to get 3 external monitors to work. Tried shutting my MBP to enable clamshell mode hoping that it would allow me to have my 3rd monitor to work since it would turn the MBP display off, no luck.

Is there any way I can get this 3rd monitor to work via HDMI or a mini DisplayPort to DisplayPort adapter?

I would be willing to allow my 3rd monitor use a usb video card knowing the frame rate will be far less (I'm not gonna run video or games on it). Would like to know what would be a good adapter that would work.

  • I had a Sewell MiniDeck 3.0 that I connected the 3rd monitor to so now I have my 15.4" rMBP, a 27" Thunderbolt, a 27" CinemaDisplay and a 27" Asus all connected. As expected, the 27" hooked up to the Sewell does have poor frame rate but enough to power HipChat and Mail.app.
    – Ajaxier
    Commented May 27, 2015 at 20:44
  • I will also say that having the Sewell displaying also, it seems my other apple displays are having some dropped frame rates too. Playing a youtube video is a bit choppy. Good thing I'm not planning on playing videos often
    – Ajaxier
    Commented May 27, 2015 at 21:09

1 Answer 1


You can run only 2 external monitors. If you want you can also run the MacBook Pro monitor, achieving in this way the 3 monitors configuration.

The only way to run 3 external monitors is to use an external graphic card to connect the third monitor.

This answer comes from personal experience and Apple technical details. I've the same model and I've tested all the possible combinations, also trying passive and active DVI connections.

  • Golden rule: MacBook without dedicated graphic card: 2 monitors + internal display. WITH dedicated graphic card: 3 monitors + internal display. Dedicated means: everything else then the "Intel Iris Pro" onboard graphic. :)
    – Sliq
    Commented Jan 31, 2020 at 19:48

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