Why 5120x1440 Doesn't Work with Apple M1

A related article on another site: https://www.macrumors.com/2020/12/23/apple-to-fix-ultrawide-display-m1-mac-issue/

I needed to turn freesync off and set it to 60hz by hand, now it shows up as 5120x1140. I hope its fixed in an upcoming update that we can use 120hz and displayport 1.4.

I also just updated to the latest beta and just set my hz from 60 to 120 on my CR49 and it works! Only freesync still on off and DisplayPort on 1.2.

5120 x 1440 is neither 4K, nor is it 6K. Every GPU has its best for display, and scaled resolutions, and the M1 GPU may simply not support that odd 5120 x 1440 resolution. Your best external resolution, presuming that your display supports it will be via a USB-C to DisplayPort 1.4 cable, or to a true 4K Display with good quality HDMI 2.0 or higher (e.g. Ultra-Speed HDMI 2.1 cables which are backward compatible with the HDMI 2.0 spec.

I have a SAMSUNG 49” CRG9, which supports 5120 x 1440 @ 120hz. It works perfectly with on MacBook Air 2020. However, on the new Mac Mini M1 I had a hard time getting 5120x1440 @ 120hz. At first the M1 wouldn’t work with the DisplayPort to USB-C cable, even after updating to Big Sur 11.0.1. I assuming it’s because the usb-c cable I had only supports DP 1.3. The HDMI cable worked but not at 5120 x 1440.  

I ordered a Maxonar DisplayPort to USB-C cable from Amazon, which supports DP 1.4. I was able to connect the monitor with the new USB-C cable, however, max resolution I was able to get was 3840 x 1080 @ 60hz. I had to change the refresh rate setting on my monitor from 120hz to 60hz and turn off Freesync. That is when I was finally able to get 5120 x 1440 (low resolution). 

I am still having a problem where the system won’t detect the monitor when waking up from sleep. Currently, I have to unplug and replug the USB-C for the monitor to connect. It might just be a problem with the DisplayPort drivers or Big Sur. I am going to try order different DP 1.4 cables to see if that fixes the problem.

https://www.amazon.com/gp/product/B08B3XNZGS/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Great info, thanks for sharing. As for cables to try, I've heard some other folks get results with this combination from Cable Matters:

https://www.amazon.com/Cable-Matters-DisplayPort-Resolution-Support/dp/B08C9NPC2S

I am not using a USB-C to display port cable. Using a High-Speed TB3 cable which is recommended for these monitors.

https://www.amazon.com/gp/product/B01N9J47EG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

16" MBP -> TB3 High Speed Cable -> Caldigit Dock -> DisplayPort Cable -> C49RG90 Monitor

There is a high-speed TB3 to Display Port cable made by Moshi that may work. I have not tested it, but others have recommended that this could be a solution

https://www.amazon.com/Moshi-USB-C-DisplayPort-Cable-1-5m/dp/B077S9DZGK/ref=sr_1_3?crid=2JTP95XSG9K43&dchild=1&keywords=moshi+usb-c+to+displayport+cable&qid=1606113487&s=electronics&sprefix=Moshi+%2Celectronics%2C151&sr=1-3

So, I need to find someone using higher-speed USB-C TB3 cable to Display Port definitively saying that this will not work with the M1.

I take it you tried, in display settings, to click the scaled option while holding the option key on the keyboard?

Were you able to push the monitor to 5120x1440 @60Hz using SwitchResX or similar display adjustment app?

Try holding option when from the monitors window. You’ll see detect display show up. I have 2 Samsung 1440p vertical monitors for coding on a 2018 iMac. The monitors are awesome but constantly tweak out from time to time. Going to settings > displays > then hitting option you’ll see the bottom right corner will swap to say detect display. Thanks for the input on the g9 though I’m looking at pairing it with the new MacBook Air via a brydge dock when that comes out next month.

Yeah I'm in the same boat of only getting switchResX to work along with that 8k usb to dp cable. Recently ordered a CaliDigit TS3 Plus dock and hoping this works as it seems to have worked for you. kinda sucks (disappointing they don't let you say s u c k s ) that I had to freaking spend $220 to get my two high end products to ******* talk to one another on a frequent and consistent basis, but if that's what it takes then fine... its a business expense anyways, but its still not ideal.

Try ScreenResX... it costs about $Aus23, it helped with recognising 120hz and is more reliable (if I unplug and plug back in, previously it would rarely detect it).

The options / fixes are (maybes), helped

1.2 instead of 1.4 Ver

60hz instead of 120hz

4k instead of 5k

Next Big Sur OS version

Connect to non M1 first and switch

Try ScreenRexX (10 day free trial)

Turn on and off with connected Cable

Option Click in display to force device detection

Premium 5k usbc to display port cable

I’ve stuffed around with it for ages, inconsistent but these all improve chances or I just give up and the hdmi @ 4K works every time. Most of my work is text based so 5k doesn’t look much better anyway ironically my old intel Mac also didn’t recognise 5k but it now works instantly every time

On the Samsung 49 inch monitors it seems if you turn on the monitor first and then the Mac mini it picks it up right away.... if the Mac mini is fired up first it’s a disaster.... and waking from sleep is a crap shoot.... sometimes it fires right up other times it’s a cord plug and unplug fiasco; definitely some issues with the Mac mini m1 variation and these big monitors.....

Use a display link. It works. They said clamshell wouldn’t work either and I’m doing it with my MacBook Air with the M1 and targus 180usz no issues with 2 1440p Samsung sh850’s

if you’re trying to do things nativity just stop you’ll **** your self off just buy a display link and you can do anything you want.

Make sure you set everything up on the monitor and then turn everything off and on.

What I’ve found is it doesn’t like plugging and re-plugging cables in and out while it’s on. If you do you’ll end up with lots of black screens and frustrations.

It is working here with this cable:

https://www.amazon.de/gp/product/B08B3SB5VC/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

and this screen:

https://www.amazon.de/gp/product/B07PQ4MPT6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

120Hz works either but in that mode it can't handle 10Bit color afaik

May I know which cable do you use and which version of macOS? Tried on 11.2 RC3 and it breaks the previously working setup.