Resolution on external display for MBP 16 M1 Max

Question

Resolution on external display for MBP 16 M1 Max

I used to have my external display (Samsung C49RG9x) seamlessly hooked up to my old MBP (2.9 GHz Quad-Core Intel Core i7) via an HMDI > USB-C cable. It works very well with a resolution of 5120 x 1440 - perfect for my business needs.

I now purchased a new MBP (16" M1 Max) and cannot connect the screen via the USB-C ports - the display is simply not recognised at all. I've tried everything, including a few hours on the phone with Apple Support, but it turned out tat the only way out was to change to the HDMI port. So I bought a new cable (10k) and now the MBP sees the display and it works - sort of. I seems that the max resolution is around 3600 x 1050 or so and I cannot seem to go higher.

Has anyone else been trapped in this corner and found a way out..? It seems pretty ridiculous that a 2021 MBP is outperformed by a 2017 MBP (although I know it's a different type of processor, but still)

I'll be thankful for all useful responses

MacBook Pro 16″, macOS 13.3

Posted on Mar 31, 2023 3:57 AM

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Answer 1

Mar 31, 2023 6:32 AM in response to Grant Bennet-Alder

Your display has one HDMI input and TWO displayPort inputs.

My recommendation is to buy yourself a USB-C to DisplayPort adapter and run away from HDMI as fast as you can.

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Answer 2

Mar 31, 2023 7:59 AM in response to Thomas_Lundberg

what make and model adapter? what cable?

The Apple-Silicon Macs seem to be asking the display if is sees any transmission errors, and if it does, it drops the connection. Also, the way a Mac recognizes a display is not intuitive:

The Mac uses a system that reminds me of “Plug and play” to determine what display is connected, and what its capabilities are.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

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Answer 3

Mar 31, 2023 6:30 AM in response to Thomas_Lundberg

HDMI is a consumer-level interface invented near the introduction of HD TV sets. It works great at 720p.

when pushed to higher data rates, it falls apart for multiple reasons, and hits the wall at 4K 60 Hz. It can only get to 4K 60 Hz if you are using high quality cables like these:

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

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The makers of HDMI wanted to go even higher, so they invented HDMI 2, which is actually a rather different take on the interface. Clocking changes, the number of data conductors changes, and the Voltage levels stay at 5 Volts, which make operation more difficult and produces so much heat that HDMI 2.0 converter get so hot they will burn your skin.

executive summary: HDMI is to be avoided above 4K, and treated as a very special case at lower resolutions.

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Answer 4

kaz-k

Level 9

51,096 points

Mar 31, 2023 5:09 AM in response to Thomas_Lundberg

Your MacBook Pro HDMI port supports till 4K(3840×2160) at 60Hz. Not sure your monitor supports this resolution, though.

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Answer 5

Mar 31, 2023 4:41 AM in response to Thomas_Lundberg

I used to have my external display (Samsung C49RG9x) seamlessly hooked up to my old MBP (2.9 GHz Quad-Core Intel Core i7) via a DisplayPort > USB-C cable. It works very well with a resolution of 5120 x 1440 - perfect for my business needs.

I now purchased a new MBP (16" M1 Max) and cannot connect the screen via the USB-C ports - the display is simply not recognised at all. I've tried everything, including a few hours on the phone with Apple Support, but it turned out tat the only way out was to change to the HDMI port. So I bought a new cable (10k) and now the MBP sees the display and it works - sort of. I seems that the max resolution is around 3600 x 1050 or so and I cannot seem to go higher.

Has anyone else been trapped in this corner and found a way out..? It seems pretty ridiculous that a 2021 MBP is outperformed by a 2017 MBP (although I know it's a different type of processor, but still)

I'll be thankful for all useful responses

Reply

Answer 6

Mar 31, 2023 6:22 AM in response to kaz-k

Thanks - and yes, I can get it to work as you suggest, but I'm more looking to find a way to make it work with the Thunderbolt ports. It works with my 6 year old MBP so I simply cannot get by head around why it won't work with a (relatively) new MBP. It's got 3 Thunderbolt ports (where the old one had 4), but no joy...

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Answer 7

Mar 31, 2023 8:07 AM in response to Grant Bennet-Alder

Hi Grant,

Thanks for taking the time..! For the "old Mac" I don't use an adapter, but simply a cable (1 × Delock USB-C 3.1 for Displayport 1.4 kabel - 8K - 60Hz). I've tried all the steps you mention on all 3 ports. It's like the display "wakes up" (goes from "pitch dark" (= when turned off) to "turned-on-dark", i.e. no signal) for a few seconds, then it goes back to sleep.

I don't see how the display can be configured to send "different" signals to the Mac, but why would that be necessary..? It works perfectly with a 6-year old Mac, but not with the M1 Max for some strange reason. Wondering if there's something wrong with the ports on the M1 Max..?

Thanks

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Answer 8

Mar 31, 2023 9:22 AM in response to Grant Bennet-Alder

Thanks, Grant

I'm impressed with on one hand all your knowledge, but perhaps even more that you bother to take the time to help me solve this /&€(/&/&)() problem.

I think I'll pursue a solution along the lines of what you suggest. I have a startup that has just gone profitable and it's of course an online business, but I'm all about "the business" and ever so often have to come to terms with my lack of tech insights. I suppose that one day I'll be sitting in my rocking chair needing help to place a phone call :D

I thought it wouldn't end like that as I'm trying to keep up, but it seems my odds are not improving.

Would you recommend that I considered a "docking bay"..?

Thank you so much,

Thomas

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Answer 9

Mar 31, 2023 9:43 AM in response to Thomas_Lundberg

Your 16-in Apple-silicon MacBook Pro has lots of ports, so you don't really NEED a dock.

I recommend you "keep it simple" and attack the error-free bandwidth of your USB-C to DisplayPort cable issue directly, and not make it more complicated by throwing other Docking features into the mix.

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Answer 10

Mar 31, 2023 10:21 AM in response to Grant Bennet-Alder

Cheers ;-)

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Answer 11

Mar 31, 2023 7:28 AM in response to Grant Bennet-Alder

Hi Grant,

Thanks, but I've already got a USB-C to DisplayPort cable - and it works perfectly from my 6-year old MacBook - full resolution; it's beautiful, but it doesn't work on the M1 Max. No signal at all...

Cheers,

Thomas

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Answer 12

Mar 31, 2023 8:45 AM in response to Thomas_Lundberg

The display interfaces contain a secondary channel. This is FAR slower way for the display and the computer to communicate. This is the channel used for the Mac to send a query to the display, and for the display to answer.

On more recent Macs, with more advanced MacOS, the Mac has the ability to say, "display, are you seeing any transmission errors?" and the display can respond.

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My assertion here is that the cable you are using is good enough for your older Mac which never asks if there are errors, but NOT good enough to support the newer Mac that actively ask the display if any errors have occurred, and backs off the resolution and/or stops sending data if there are ANY errors.

In my opinion, it would be worth the trouble to try a different USB-C to DisplayPort adapter.

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