[Mac M] Refresh rate max 30Hz on both 4k AND lower res?

jonathan.pl · April 8

Hello,

I have a problem with a Mac display settings. I write here because it's clearly an OS problem.

I have an M1 Air, and I just bought a nice TV. The screen supports HDMI2.1 (4K@120), but I use an adapter that appears to be limited to 4K@30.

And 4K@30 works fine, except Mac UI scaling is garbage so I'd rather use 1440p. – And here's the problem: I can't change refresh rate to anything above 30fps! (25 I can )

If 4K@30 is supported, then 1440p@60 should be too – I tried the adapter on a different machine (Win11) and it does work there. Moreover, on the Mac even 1080p is limited to 30fps. WTF?

Is there like a hidden function, or do I need to resort to homebrew solutions?

Cheers,

—J

jaslion · April 8

The adapter you have may be a bit wonky and not work great on every port.

Is it a usb c to hdmi one? I have run into issues a lot with usb c display adapters being odd.

jonathan.pl · April 8

On any other machine this is the best adapter I have. Has VGA, HDMI and USB3.0 and gives me no trouble whatsoever.

Even when I used this very same adapter on the very same port of that same Mac on a 3440x1440p screen, it was able to give me 50Hz. (Also via HDMI connection.)

Isn't there a CLI call, or some fancy-shmancy "Press along with Option-key" option, equivalent to "Show unsupported modes" on Windows?

I lack Mac experience, but I did my research and found nothing...