I have the latest MacBook Pro - Can I buy two and use them in tandem as a dual monitor set? Do the monitors daisy chain?

You can buy 2,3, or 4 and use them in tandem. They do not daisy chain though.

The LG 4K display does not have a DisplayPort output to support daisy chaining.

The LG 4K is a USB-C display (USB-C with DisplayPort alt mode, using DisplayPort 1.2 (4 lanes), and USB 2.0).

I don't know if macOS supports DisplayPort MST (for daisy chaining displays using DisplayPort). The MacBook Pro supports DisplayPort 1.2 which can't support more than one 4K 60 Hz display anyway.

Each side of the MacBook Pro (left side and right side) can support two displays. The MacBook Pro 15 inch allows up to four 4K displays. The MacBook Pro 13 inch allows two 4K displays.

Thunderbolt 3 can support two 4K 60 Hz displays from a single port using Thunderbolt display daisy chaining, a Thunderbolt 3 to Dual DisplayPort or HDMI 2.0 adapter, or a Thunderbolt 3 dock. However, I am unaware of any Thunderbolt 3 product that has more than one USB-C port with DisplayPort alt mode (required for USB-C displays like the LG 4K).

It might be possible to use an LG 4K with DisplayPort only (no USB) by using a USB-C to DisplayPort cable, but then any functions of the display that require USB will not be usable (audio, brightness control, USB hub). Brightness control may be possible using an app that uses DDC/CI.

To get two ports supporting USB-C with DisplayPort alt mode from a single Thunderbolt 3 port (so you can use the other 3 ports for other stuff), you need the following:
1) two Sunix UPD2018 or two Delock 89582 (PCIe USB 3.1 gen 2 host controller with USB-C DisplayPort alt mode port).
2) one Thunderbolt 3 PCIe expansion box with two or more slots such as the Sonnet Echo Express SE III, or two Thunderbolt 3 PCIe expansion boxes each with one slot such as the Sonnet Echo Express SEL (Thunderbolt 3 Edition).
3) one Thunderbolt 3 to Dual DisplayPort adapter such as the one made by Sonnet (not all Thunderbolt 3 products are Mac compatible so check the manufacturer's specs).

• Answered by Joseph V from Fort Langley
• Feb 25, 2018
• Flag as inappropriate Answer 1

What Joseph V from Fort Langley says is 100% accurate. I have 3 monitors at work with a 15 macbook pro with touchbar. One side of the macbook is plugged into a caldigit usb-c dock, and two monitors are plugged into the caldigit. This handles both rendering to the monitors, as well as charging the macbook. The third monitor is simply plugged directly into the other side of the macbook. However, my boss has a 4-monitor setup with 2 caldigit docks - one plugged into each side. Works a treat, but you'll need to make sure you have the right adapters to go from the back of the caldigit dock to the monitors; or find another dock that has all the outputs you need for 2 monitors.

What I'm sure of, is that because of the way the macbook was built, and the type of chip it has, only 2 monitors can be plugged into each side of the macbook. 2 on left, 2 on right. If shooting for 5k, than it's 1 on each side.

Daisy-chaining is a definite no-go. I actually went into the apple store and the guys working weren't sure if daisy chaining was possible, but were as curious as me to find out. So they basically reorganized an entire shelf to try it out in front of me. No-go. As far as multi-monitor support, what we found was 2-monitor support for 5k displays, and 4-monitor support for 4k displays. The displays, however, are able to be the last node in a daisy chain of other perifs. For instance, macbook to external hard drive to monitor works well.

• Answered by Timothy A from Chandler
• Jul 5, 2018
• Flag as inappropriate Answer 3