MacBook – Connecting 3 monitors to macbook pro 2018 via thunderbolt 3

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I looked for 20 minutes for a post similar to mines, and couldn't find one. Which is interesting to me, because I don't understand why people want to use the display to HDMI instead of using thunderbolt USB-c port natively instead. Before I get to this…I shall ask my question.

I plan on buying a MacBook Pro-2018 15 inch for my home-based business. I need to connect 3 monitors to this laptop. I understand the 15 inch MacBook Pro comes with 4 thunderbolts 3 ports. I plan to buy 3 24-27 inch monitors that are 4k display. Also, I understand that the charger for this laptop uses a Thunderbolt 3 port, which leaves me with 3 left. Will connecting 3 monitors that have Thunderbolt 3 ports leave me with performance issues? Will the refresh rate lower?

Finally, why do I see a lot of post with people using old 2.0 display port to HDMI; why they can use Thunderbolt 3 port natively?

Best Answer

I currently use 3 4k displays (Dell P2715Q) on a MacBook Pro 15" 2017 (GPU: Radeon Pro 560 4096 MB).

Two monitors are connected to the right side ports/bus and the third one (plus a dock for charging/USB/etc) are connected to left side ports/bus. The monitors are arranged in a "H-shape" with two monitors flipped 90 degrees.

I've had this setup for about 6 months now and while it is usable, I do face some issues from time to time, always after waking up the monitors after sleeping overnight:

  1. The orientation (90 degree rotation setting) tends to get messed up in two of the three monitors and I have to waste 1-2 minutes fixing it on System Preferences > Displays. The cause for this likely a software/compatibility issue on macOS and I have had this on a two monitor setup as well.
  2. Every now and then the ONE of the monitors connected to the right bus fails and I can't make BOTH work again without a system reboot. By repeatedly disconnecting/reconnecting the mDP cables I can get EITHER of them to work, but often not BOTH simultaneously, which is pretty annoying. I feel like this is a hardware issue, perhaps GPU memory issue, but more likely something to do with the Thunderbolt bus bandwidth as it always happens to the bus that has 2 monitors attached to it and never to the one that has only a single monitor attached to.

TL;DR: It is possible but be prepared for some minor issues and eventual monitor "loss" followed by a system reboot.

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