I have a Mac Pro 2013. I already have two 4k monitors now connected to

the HDMI port (Bus 0) a thunderbolt port with a TB->HDMI adapter (Bus 1) Before I simply buy a third monitor and adapter, is it as easy as that?

Do I just plug another adapter into the last BUS that isn't being used? (I understand to separate the monitors on different buses.)

FYI, I tried a 3rd monitor that wasn't 4k and it didn't fire up/get recognized. I read somewhere on Apple's site that once you have one 4K monitor connected you need all of them to be 4K.

  • Beau, did you ever get an answer to this? Which TB->HDMI adapter were you using at the time?
    – Clark Rhee
    Commented May 14, 2019 at 0:44
  • I haven't tried a 3rd monitor yet. I am using a no-name brand adapter for my second 4k that works fine, but any 3rd monitor I have is not 4k so they are not getting recognized. Commented May 18, 2019 at 19:25

1 Answer 1


The main article on 4k displays links to the below article on Mac Pro:

The trick for the third display on Mac Pro is to use 2 Thunderbolt and one HDMI cable to connect each directly to the Mac Pro. Basically each bus can handle 2 normal displays or one 4K display each.

Three 4K displays: two connected via Mini DisplayPort and one connected via HDMI

You are correct about bus 0 conflicting with the HDMI adapter as well.

Mac Pro bus layout from https://support.apple.com/en-us/HT202801

If you're not on the 2013 Mac Pro - see this thread for options for "unsupported" adapters that might work for lower resolutions or lower refresh rates than the native ones.

How can I run 3 4K monitors on my 2015 MBP

  • so, yes to my answer?. just use another TB->HDMI adapter for the third? Commented Sep 14, 2017 at 17:51

You must log in to answer this question.

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