How to? Connect MBP 2017 15" to 4 Dell P2715 monitors

User008

macrumors newbie
Original poster
Oct 24, 2015
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I have the 2017 15" MBP with 4x TB3 (USB-C) ports [specs here].
I also have four Dell P2715Q monitors (each with HDMI, DP, and mDP inputs) [specs here].

I'd like to have 5 independent, not mirrored, displays (4 Dell monitors + the laptop screen). What is the best way to do this? I see several "1-in 4-out" HDMI splitters available, but some reference MST and Apple's lack of support for it. It appears that there are some "1-in 2-out" HDMI splitters, but the only examples they give are for mirrored displays.

Surely there's a better option than buying 4 Apple Digital AV Adapters, right? What's the best way to get 4 independent external displays running off this MacBook?
 

techwarrior

macrumors 65816
Jul 30, 2009
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Colorado
According to everymac.com, 2017 MBP 15":

*In addition to simultaneous support of the internal display, this model supports a maximum resolution up to 4096x2304 at 60 Hz at millions of colors on four external displays or two external displays at a maximum resolution up to 5120x2880 at 60 Hz at over a billion colors via Thunderbolt 3 (USB-C).

One of the TB3 ports is needed for power, so an adapter with power pass through and a TB3. or HDMI port would be needed, in addition to 3 USB-C\TB3 to HDMI, DP, or mDP adapters or cables. Don't forget USB ports as well for other peripherals.

I have had good experiences with the cheaper cables\adapters from Amazon. No need to pay the Apple tax for decent video cables. I even had an Apple Store employee suggest this approach due to the high price of Apple's cables and docks. The Digital AV Adapter you linked to may be a good bet for the one port where power is supplied, though you can find similar Amazon offers for $20-30. The rest of the ports can be a $10-20 TB3 to HDMI (or DP\mDP) cable or adapter. I prefer the cable approach, it results in a cleaner setup.
 
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User008

macrumors newbie
Original poster
Oct 24, 2015
26
120
I have one of the linked Digital AV Adapters for work and bought two USB-C to DP cables on Amazon last night, so I'll see how well those work. This seems to be a much better solution than some of the $200 docks I was looking at.
 

theluggage

macrumors 601
Jul 29, 2011
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Surely there's a better option than buying 4 Apple Digital AV Adapters, right? What's the best way to get 4 independent external displays running off this MacBook?
Don't forget USB ports as well for other peripherals.
...therein lies the snag - No "USB-C**" dock or adapter can support USB 3 ports and a 4k@60Hz display at the same time - since all 4 of USB-Cs high-speed data lines are needed to provide a full-width DisplayPort stream and all you get for data is the fallback, much slower, USB 2 channel.

So if you want to connect any USB 3 devices, at least one of the displays will need to be connected via a (more expensive) Thunderbolt 3 dock or adapter. Thunderbolt 3 combines 2 x DisplayPort streams with data on the same wires, and doesn't have that restriction. Best solution is probably something like a Caldigit Thunderbolt Station 3+ which should give you USB 3, charging and drive up to two of the displays (one via a DisplayPort cable, the other via a USB-C to DisplayPort cable) leaving a free port on the Mac.

Caveat: there may be cheaper ways to do this using a TB3-to-dual-DP or HDMI adapter that will free up a Mac port for power/USB but whatever device you get you need to make very, very sure that it (a) uses TB3 not USB-C and (b) is a newer TB3 device that can support two independent 4k@60Hz Displays - some of the older offerings rely on DisplayPort daisy-chaining that won't work on a Mac (and won't do 4k@60Hz x2 anyway).

NB: I haven't actually tried any of this :)

** As in 'USB-C featuring USB 3.1 and DisplayPort alt mode but not Thunderbolt' as opposed to devices with a USB-C connector. Complaints on a postcard to the USB name-thinking-up people.