Why 5120x1440 Doesn't Work with Apple M1

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

Hey all, my setup has the Samsung G9 with the M1 Mac Mini, and a desktop PC with an RTX2070. Watching some youtube vids, i made sure to buy a direct DisplayPort to USB-C cable that supported 1.4. I thought that would solve the issue, however, i still had to do some tinkering, although i think you'll still need a direct cable with DP 1.4 support for this to work.

Before playing around with the settings on the computers and the monitor, switching around and wake from sleep bugging out on the Mac Mini was really annoying. Even with the 1.4 direct DP > USB-C cable.

However, I think i've landed at a config that works, although this still requires the use of SwitchResX. Hopefully this will help some of you, there's a trial so you can try anyway.

G9 Monitor Settings:

Game: Refresh Rate > 120hz (240hz would bug out on wake from Mac)

Game: Adaptive Sync > off

System: DisplayPort Version > 1.4

Driver Version: 1008 (get from samsung site, requires a usb stick)

Mac Mini:

• Used SwitchResX to set the display to 5k 120hz.
• Setting Monitor to 240hz seems to bug out when i switch from PC > Mac, setting it to 120hz seems to not have this problem.

Mac OS: Big Sur 11.0.1

So my final judgment.

I am keeping the Mini M1 ...I am returning the MacBook Pro M1 (I was to keep one of the 2)

My monitor is the Samsung Odyssey G9 (5120x1440)

I need a Caldigit TS3 for my use case.

The mini has flaws/bug but none are visible anymore if I use the TS3.

MacBook is excluded on the simple fact that it supports only one external monitor (otherwise it was as good as Mini).

Bugs / annoyances

• MX master mouse skips when on Bluetooth ...solved my using Logitech dongle (and possible because of extra USB ports offered by TS3). Dongle is plugged in Mini directly.
• Display port won't wake up ... solved when using TS3 (but there is clearly a problem with mini there on diplayport)
• Small pink dots on HDMI monitor... still there but rare and only lasts a couple of seconds.
• Mini does not offer enough ports... solved with TS3.
• Mini does not detect full resolution and refresh rate ... solved with SwitchResX
• Home Office Headset does not work well in Bluetooth .. solved by plugging Jabra base though USB (headset remains wireless)
• Dual monitor mode ( picture by picture / dual cable) . Works (one DisplayPort cable going to TS3, one HDMI cable going to mini). This is my main daily use mode.
• Ultrawide mode (5120x1440 @ 120Hz) works, display port through TS3, + switchresx + unplug the HDMI cable (otherwise i get phantom monitor). I dont need ultra wide when using mac... so no big deal here... I use the ultra wide with Windows through the other DisplayPort.

Essentially in the morning I walk to the mac ... tap the keyboard which wakes and unlocks the mac with Apple Watch.. then start using my picture by picture monitors for work. No fiddling. Left side Citrix.. right side Office 365.

As for the MacBook if I had chosen to keep it I would have had to let go of my picture by picture mode and I just can't.

For gaming I switch to my PC and use the same monitor 5120x1440 @ 240Mz with Gsync. All good.

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.

But the discrete Radeon GPU on that 16 inch 2019 MBP very likely supports far more resolution choices than Apple has provided in the 8-Core M1 GPU, when using the same cable. Nothing you can do about it, if it doesn't.

Yeah, I forgot to mention ScreenResX, as I don't use it. The font size will be microscopic, and not certain you can have that screen resolution and larger fonts in menus, etc.

When my M1 mini arrives, I will be testing it with a 40 - 43 inch TV as a Desktop, so ScreenResX may play a role there too.

What do you mean you can't scale? Is there no option or is it not working? Did you hold down the Opt key when you clicked on the Scale Resolution radio button to get the expanded list of resolutions to scale to?

I am awaiting delivery of a Mac Mini M1 and plan to connect it to a 5120x1440 ultrawide display as well. I hope I can make it work with a reasonably comfortable scale option. If not, I'll try doing a Picture-by-Picture setup with the HDMI and TB3 ports feeding the monitor and doing a side by side arrangement. It's not perfect but at least I'll be able to use the entire display as two monitors next to each other.

Actually, your picture by picture idea is not bad. I use a samsung g9 monitor with a windows gaming rig and wanted to use the M1 for work (citrix and office 365 web). 2 side by side on the G9 would actually probably be ok.

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

My 16" MBP works fine with my Samsung 46" UltraWide monitor at 5120x1440.

I do have ScreenResX installed.

This is my connection:

MBP -> 4k 60Hz TB3 cable (40Gbps) -> Caldigit Dock -> Display Port Cable -> Samsung Monitor

With that connection is there any suitable resolution I may be able to obtain with a Mac Mini M1 connected the same way?

I have the same Samsung C49RG9x display and the new base M1 MacBook Air.

Using this adapter - https://www.amazon.com/gp/product/B07F17ZHJY/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I also had to set the monitor setting to FreeSync OFF, 60hz; but could only set the 5120x1440 resolution using SwitchResX.

One other note I have is that 120hz refresh rate was possible @ 3840x1080 with EasyRes.

5120x1440 @ 120hz is still not possible with the combinations I've tried.

I was finally able to get full 5120 x 1440 and solved the monitor not waking up after going to sleep. I tried the Cable Matters Display Port DisplayPort to USB-Cable and the adapter. However, the one that I found to work the best was the Maxonar DisplayPort to USB-C cable from Amazon.

To get full 5120 x 1440, I changed the DP settings from 1.4 to 1.2 on the 49" CRG9 monitor. Also under System Preferences on the mac there is hidden display option. System Preferences -> Displays-> Press and hold the Option key on the keyboard (that will bring up Detect Displays -> Click Detect Displays.

As I noted above I am using high-speed Thunderbolt 3 cable which is quite expensive to run a connection from my 16" MBP to my 49" Samsung UltraWidescreen display.

Nobody is talking about results using this Thunderbolt 3 connection with the new M1 mini so I am hoping that when I finally get my Mini in December I will have no display issues.

NJ Ron, I assume you mean you are using a USB-C to DisplayPort 1.4 cable that is plugged into a Thunderbolt 3/USB C port on your MBP 16” because the CRG90/G9 does not have a Thunderbolt 3 input?

If so, I have the same setup and my MBP works fine but my M1 is having tones of issues with DisplayPort (as many in this thread have stated). And HDMI on the M1 only seems to works up to 3840 x 1080 @100hz HDR.

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?