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thejadedmonkey

macrumors G3
Original poster
May 28, 2005
9,359
3,822
Pennsylvania
I'm just really annoyed and feel like complaining 🤣

I have a $3000ish 2018 Macbook Pro from work sitting on my lap right now. It's got everything but the kitchen sink in it, and if I plug in a USB-C cable, it connects to a single monitor and USB devices and everything is nice, except that my 2nd external monitor is a mirror image of the first.

I also have a $600 Surface Go, which is hardly the paragon of high end computing. It also has a USB-C port, and if I plug it into my USB-C monitor, it connects to my monitors and peripherals and everything is perfect. The difference is that it connects to my monitor, and the 2nd monitor that's daisy chained to it. Just. Like. That. My desktop is extended across 2 QHD screens plus the internal screen. My Macbook Pro that costs almost 4x as much can't do that. Apple insists that 2 monitors need some sort of docking station (aka a super-special dongle) or multiple cables.

Imagine my surprise when I plugged my daisy chained monitors into my desktop. It's an old device, with a GPU from the dinosaur age (early 2012!). And the single display port cable carried the signal for both monitors. This is 9 year old technology, and Apple doesn't support it.

Technical aside: Sending multiple video streams through a single USB-C cable relies on a protocol called DisplayPort MST. Apple simply refuses to implement it. If you install Windows on a Macbook via Bootcamp, the hardware supports MST and multiple monitors via a single cable will work.

So here I am, not quite sure what part of my MacBook Pro is really pro level. It's certainly not the butterfly keyboard, nor is it the port selection. It's not the capability of the laptop to drive multiple monitors. It can't max out the CPU without the battery draining multiple percentage points in a minute, and it certainly gets hot and loud when you push it.

Really, it's a mediocre device, and I'm just so sick of compromising to compensate for Apple's inability to make something that's actually functional.
 
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Sending multiple video streams through a single USB-C cable relies on a protocol called DisplayPort MST. Apple simply refuses to implement it.
Yep, that's it. Quite annoying really. MST has been introduced in 2010. Strictly speaking, macOS does support MST - for tiled 4K displays.
 
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Likely you have your MacBook set to mirror the display.

Go to System Preference > Displays > Arrangement.

See https://support.apple.com/guide/mac-help/use-multiple-displays-mchl7c7ebe08/mac

Thanks for the help, but sadly that's not the issue here.

From the page you linked to:
For Mac computers with Thunderbolt 3 (USB-C): You can connect a single display to each port. If you connect multiple Thunderbolt devices to each other, the Thunderbolt 3 display must be the last device in the chain. If your Thunderbolt 3 display has USB ports, those can be used for data and power.
 
I agree it is really frustrating that Apple hasn't implemented MST. You would think given the limited number of physical ports that Apple would have implemented this the day they switched to USB-C.
 
Made an account here just to say that this has been hugely inconvenient for me too during COVID for my wfh setup, my desk is a mess of cables and I’m using every usbc port on my MacBook Pro and had to spend extra on buying extra adapters and cables just to be able to use my two existing monitors easily

Edit:
Look at this ugly adapter that exists because of the limitation -_-
It should not need to take up two usbc ports!!
1629441065012.png
 
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Everything about external display support on MacOS is just plain horrible.
  • HDR support is flaky and might not work even on TVs.
  • There is no way to set bit depth and chroma subsampling. My LG TV defaults to 10-bit 4K 4:2:0 and the only way to make it run at 4:4:4 was a DisplayEDID override that disables 10-bit support.
  • The noise issues due to excessive GPU usage just by having an external display connected to my 16" MBP.
  • The user interface ridiculousness. Why do I nee to check "show low resolutions" to show refresh rate settings?
  • My old 144 Hz monitor was only able to run at 120 Hz on my MBP.
  • The same adapter that allows for 4K 120 Hz via DP to HDMI 2.1 on my PC only works at 60 Hz on MBP no matter what.
  • 4K high refresh rate support can be flaky, there's even lists of what works and what doesn't while on PC all of these displays work just fine.
  • HiDPI support is artificially gated just because. It can go missing from 4K monitors, it does not work on 1440p monitors. How about Apple lets us choose if it's an acceptable option or not?
 
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