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?

LG UltraFine 4K Display

LG UltraFine 4K Display

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2 Answers from the Community

  • Answer

    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).

  • They don’t daisy chain (least not as far as I can tell) but you can use two by plugging them into two ports in the MBP.