Why 5120x1440 Doesn't Work with Apple M1

MSAGA146,

I have the same exact monitor and it's working beautifully with the M1 Mini.

You need to be on Big Sur 11.2. Not sure if it is out of public beta or not. I think it was just released.

THEN you can get the resolution you are looking for. If not, you can do so with the help of SwitchResX software.

I have no issues with waking up the monitor. There was a one-time issue where I woke up the monitor and there were all these color distortions. I just rebooted the M1 Mini and it was fine. Only happened once. Otherwise, having much success here.

A USB-C to DisplayPort cable is just a cable - it does not fix problems with the source. It can do 8K only if the source supports 8K. Maybe the USB-C ports of an M1 Mac have voltage or signal problems or don't read the e-marker chip of some cables properly or something like that. Putting a Thunderbolt dock between the M1 Mac and a display can clean up the signal. An M1 Mac that can't get out a proper DisplayPort signal may be able to get out a Thunderbolt signal. A Thunderbolt dock takes Thunderbolt data from the M1 Mac and recreates a DisplayPort signal from that.

I use the M1 MacMini with a Dell U4919DW curved monitor with native 5120x1440 resolution with a direct connection via the original USB-C cable from the monitor supplied accessories. The M1 MacMini I received today is running BigSur 11.0.1 and worked at once with the right setting and auto negotiation. So the resolution seems not the issue.

Maybe the resolution Frequency combination is a hurdle for the Samsung on the HDMI since the Monitor offers 120Hz as far as I know.

I also have a Samsung Odyssey CRG9 49 curved Monitor and can confirm, that this monitor refuses to offer the full resolution over HDMI and falls back to 3840x1080. I did not test any Display-Port cables. It is either a limitation of the HDMI/Cable combination or the EIDE Firmware in the Samsung that offers the wrong data or the M1 is not able to negotiate well.

The Samsung offers by default only 3840x1080 60hz on a Gigabyte BRIX Windows 8.1 machine with a dedicated Geforce GTX760 . It can then be forced without special tools to use the full 5120x1440 with 30Hz in the System Configuration (marked as not recommended).

I did not try the "Alt-Click" on "Scaled" method in the M1 MacMini "Resolution Settings" for the Samsung yet.

I found this on another forum and this worked for me:

holding down the options key when you are in Display settings on the Mac to see extra available resolutions. Some say they can do it with SwitchResX installed (or similar software).

I do not have SwitchResX or anything installed and this worked on my LG 49WL95C-W 49" monitor. I hope this helps.

Clearly there are still issues that Apple has yet to resolve, but that doesn't negate the fact that for some of us, 5120x1440@120hz is working perfectly fine through bootup, sleep, wake, and shutdown as expected. It all comes down to the combination of cable and monitor and settings on the monitor. Admittedly, I had issues early on, but once I got it working, it's been stable. The resolution is pixel perfect for 5120x1440, not zoomed in or out, jagged, fuzzy, or distorted. Using an AOC AGON 49 Super Ultrawide and the Cable Matters USB-C to DP adapter + DP cable. I'm running SwitchResX because it helped before MacOS was updated and I just never uninstalled it.

Great News. Just installed 11.2 Beta 2. DP 1.4 Works, 5120x1440 Resolution works with 120Hz .... well good Job Apple

So I’ve finally fixed it.

Big Sur 1.2

Samsung CR49 Ultrawide monitor

5120x1440 120hz

Freesync Ultimate Engine

Display Port 1.4

No additional software or boxes. System happily sleeps, wakes and reboots.

Cable £22 from Amazon

https://www.amazon.co.uk/dp/B08B3SB5VC?ref=ppx_pop_mob_ap_share

This cable gives me 120hz @5120x1440 with no issues. Have to use it on DP1.2. It does not work with DP1.4 setting.

Cable Matters 8K USB C to DisplayPort Cable (USB-C to DisplayPort 1.4 Cable/USB C to DP Cable) 8K@60Hz, 4K@60Hz, 2K@144Hz in Black 1.8m - Thunderbolt 3 Port Compatible for MacBook Pro, Dell XPS https://www.amazon.co.uk/dp/B01LYD2Y19/ref=cm_sw_r_cp_api_fabc_JX4NDVT3BGQXKNYQ0XK4?_encoding=UTF8&psc=1

Set the Monitor manually to 60Hz. At least for me I can't choose 5120x1440 if the Monitor is set above 60Hz except if I use SwitchresX

Monitor to 60hz

Then you need to press Option/Alt while pressing the scaled button in OS X Displays.

I can have 5120x1440@120Hz without any issues, on CRG9 with standard DP cable and UGREEN mm130 usb-c adapter (which is rated 4k@60) + DPv1.2 in settings.

Just wanted to pop in here and give some good news...

Just bought my first Mac Mini. Of course, it's an M1.

My biggest fear was that it would not drive my 46" Samsung CRG9 (I think that's the model).

Taking the advice of a YouTube video, I installed the next version of Big Sur. I'll let you figure that out. My post was removed by the agressive moderation here in trying to help people get their display problems fixed because I mentioned the "B" word.

In any case, I was immediately able to get 5120x1440 resolution in my choices of 60Hz, 100Hz and up.

My display is performing wonderfully. No issues whatsoever.

I am using a 40GB/60HZ TB3 cable from the Mini to a Caldigit dock. Then from the Caldigit dock I use an ordinary display port cable.

Amendment to my previous post. Everything works but if I set DP1.4 on the monitor it won’t wake from sleep so I’ve left it at DP1.2 and everything works fine.

Really not sure what the DP1.4 issue is. It is a 1.4 cable.

Is the display connected directly to the DisplayPort 1.2 port of the TS3 Plus?

https://www.caldigit.com/ts3-plus/

Either you're not connected directly to the TS3 Plus, or you're not using 5120x1440 120Hz or the pixel format is not 4:4:4. I don't know how to get pixel format from macOS on M1 Macs, but the script at https://gist.github.com/joevt/e862b0088ef58b9144877d01401bcee8 should show what timing you are using.

You could be using 5120x1440 scaled down to 3840x1080@119.974Hz