MacBook Pro M3 Pro with Samsung Odyssey G9 OLED Smart

I had similar kind of issues: my M3 MacBook didn't identify the screen correctly and only offered a subset of the resolutions available. I decided to use BetterDisplay (https://github.com/waydabber/BetterDisplay) and manually set the display information, after which everything started working fine.

However, this is just an ugly workaround. There's definitely something wrong with M3 HDMI port/driver: I've tried several cables and none of them identify the display correctly. When using PIP (I'm using G9 with PIP, both HDMI + Display port connected to my M3 = 2x 2560x1440), I can't use the MacBooks HDMI port because of the previous issue. I'm using usb-c -> displayport & usb-c -> hdmi cables instead.

Your MacBook Pro 16-in from 2022 or later supports HDMI 2.1, so it should work for HDMI displays up to 8K in size. That 5K display should not be an issue.

Whet has been vexing users at every turn is that cables "shipped in the box' tend to be 'lowest bidder' cables, just good enough to keep you from returning the device the same day.

Recent version of MacOS INSIST that data transmission to the display be completely error-free, or the resolution is reduced at the Mac end until it becomes pro free. HDMI 2.1 on a Mac that supports it requires CERTIFIED ULTRA cables.

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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.

HDMI was invented for HD TV sets. it works great at its original resolution of 720i or 720p. At higher resolutions, it quickly develops issues that are complex to solve, and the cables and adapters required to solve are NOT intuitive.

Higher than 4K displays can only work DIRECTLY connected to HDMI port (NO ADPAPTERS) using ULTRA 8K-rated Certified HDIMI cable, or

Direct-connect USB-C shorter that 1 meter, or

Direct-connect Thunderbolt cable shorter than 0.8 meters for Apple cables, 0.5 meters for brand-X cables.

Adapter/cables must have the adapter electronics within the first 1 meter of the computer-end, and you must select carefully.

Most Docks will not work at all at resolutions this high, Thunderbolt docks are slightly more likely to work.

The restrictions come because later versions of MacOS are increasingly enforcing 'no transmission errors allowed'. So to compare to other Macs, you must be running the same version of MacOS.

Windows really does not care what you connect or how, "It's your problem if it makes errors." So "it works with Windows", does not support your case in any way.

Have you tried ticking the 'show all resolutions' box? I have the 13" M1 MBP and it offers only 3840x1080 by default but if I tick the 5120x1440 which is funnily labedled 'low resolution' I get the native resolution.

I also found out that my USB-C dock limited my resolution to 3840x1440. When I switched to a displayport to usb-c cable I get all the native resolutions, including 5k@240hz (edit: oops the option is gone now after I set it to 120hz to test if the prior flashing problems on the M1 were refresh related). The flickering problem that occurret on high contrast image ares on the M1 is now gone with the M3 pro.

These forums have been great, but there is no magic bullet cable/solution so far.

I've downloaded SwitchResX, and this allows me to get to 5120 x 1440, 60hz, anymore and i get the green light at the bottom.

This software does allow 10 days for free, then you have to register for £12. Have to say, it worked really well, but I'm still more than frustrated at the cost of this display, and not having a seamless/enjoyable experience.

https://www.madrau.com/srx_download/download.html

If you're using any sort of adapters or hubs, that is most likely the issue. I couldn't get a full resolution through a USB-C hub either. But with a direct DP to usb-c cable I can get full native resolution at 120hz.

I also found out that my USB-C dock limited my resolution to 3840x1440. When I switched to a displayport to usb-c cable I get all the native resolutions, including 5k@240hz. Also the flickering problem that occurret on high contrast image ares on the M1 is now gone with the M3 pro.

Yes for me all it took was the Club 3D DP to USB-C cable directly connected from the monitor to the MBP.

Not exactly the same setup but with a 2021 intel pro and a Neo G9 I can only reach full resolution with the DP port.

There are some similar cases on Reddit.

I came to this thread hoping to find this fixed in theM3, but i'd better wait for Sammy to release a G9 with two DP (the spare one goes to my gaming setup)

Im not sure how did I resolved this problem, but it’s working now

I did update my system because there were some minor updates available and I restarted laptop and plug this cable:

1.8m DisplayPort-thunderbolt

https://allegro.pl/oferta/kabel-mac-macbook-usb-c-displayport-8k-5k-4k-240hz-10657757168

also this cable goes not directly to laptop but to dell dock station.

everything is working right now but

i can make 4K @ 240Hz

and 5k2k at maximum 120Hz

so I’m not sure if this is limitation of m3 max

on the Reddit I read that someone with cable UHBR13.5 can handle 7k tv with rx7000

https://www.reddit.com/r/ultrawidemasterrace/s/uHKQ8Twlkt

You can also set aside AirPlay and connect using two "real" data cables, one for each Left-Right Half of the display. Picture-by-Picture in the display and Arrange pane in the Mac work together to put the picture back together. Users who have tried this, report displays that support it work well this way.

that cable/adapter, at 1.8 meters of USB-C cable before the conversion electronics, is too long for top performance. It should have no more than ONE meter USB-C section.

Regular Rockfish HDMI (not 2.1) for the HDMI to HDMI input, BolAAzuL Active 4K HDMI to... https://www.amazon.com/dp/B07Q3VDXN8?ref=ppx_pop_mob_ap_share, HDMI to DP. The HDMI to DP is plugged into an Apple USB/HDMI/USBC to USB C adapter