Help: M4 Mini limited to 4k @ 60hz over 8k HDMI 2.1 cable

[EvilEvil]

I just got my M4 Mini and plugged it into My LG C2 4k OLED TV and can only get 4k @ 60hz max. I thought it was supposed to support 4k @ 120hz over HDMI?

 

[Bigwaff]

I just got my M4 Mini and plugged it into My LG C2 4k OLED TV and can only get 4k @ 60hz max. I thought it was supposed to support 4k @ 120hz over HDMI?

Make sure your LG tv HDMI settings are set to "enhanced" and "HDMI 2.1"

 

[Cosmo M3]

General > External Devices > HDMI Settings > HDMI Deep Color > 4K

Did you not have that activated this whole time?

Also make sure you change your HDMI input to "PC" in the TV Settings.

 

[EvilEvil]

General > External Devices > HDMI Settings > HDMI Deep Color > 4K

Did you not have that activated this whole time?

Also make sure you change your HDMI input to "PC" in the TV Settings.

I just checked. It's greyed out and won't let me change it. Is my HDMI cable the culprit?

 

[Cosmo M3]

I just checked. It's greyed out and won't let me change it. Is my HDMI cable the culprit?

Probably. You need a HDMI 2.1 cable.

 

[EvilEvil]

Probably. You need a HDMI 2.1 cable.

The one I have is HDMI 2.1 It worked with my gaming PC no problem. It must finicky with my Macs.

 

[eba]

The M4 Mini definitely supports 4K 120Hz. Works fine on my LG C4 - no tweaking necessary, just plugged it in. I suspect your cable.

 

[EvilEvil]

The M4 Mini definitely supports 4K 120Hz. Works fine on my LG C4 - no tweaking necessary, just plugged it in. I suspect your cable.

It indeed was the cable. I just tried another cable and it worked!

 

[foojesus]

It indeed was the cable. I just tried another cable and it worked!

Hey, I'm still waiting for my M4 Pro mini to deliver, and I intend to use it with my LG C3 and an ASUS ROG OLED monitor side by side. could you confirm with your C2, you're able to have 4K 120Hz HDR from the mini? and what's your resolution scaling?

the experience I've had with this TV and my M2 Max laptop, is that if I want HDR, the maximum resolution scaling and refresh rate is 1440p and 100Hz, anything higher would make me lose the HDR option, and the non HDR on LG C3 looks awful for macOS.

 

[Cosmo M3]

@foojesus I can confirm my base M4 mini gets 4k 120hz with HDR if you use the proper cable on my LG C2 42". The MacOS resolution scaling is kinda wonky, so I don't use HiDPI and just leave it at default 4K resolution.

 

[throAU]

I just checked. It's greyed out and won't let me change it. Is my HDMI cable the culprit?

Could be. HDMI sucks. I've had all manner of problems with HDMI cables.

I can confirm that i am able to run 4k @ 120 (or higher i forget, maybe 144 - my montor is 160hz, just remember 160 doesn't work) on an M1 pro via USB-C. I would expect the M4 to do as well or better than that.

 

[foojesus]

@foojesus I can confirm my base M4 mini gets 4k 120hz with HDR if you use the proper cable on my LG C2 42". The MacOS resolution scaling is kinda wonky, so I don't use HiDPI and just leave it at default 4K resolution.

yea the UI in native 4K is just too small to read. I did some digging, with resolution scaling like 1440P, macOS is actually rendering 5K (2880p) and then sizing it down to 1440P to the monitor, however 5K120HzHDR requires more bandwidth than what HDMI 2.1 can achieve.

monitors that support high refresh rate achieves this by have DSC implemented that compresses the stream while having no visibly artifacts. However, LG C series TV does not implement DSC, hence it cannot achieve 4K120Hz at HiDPI with HDR on macOS.

 

[eba]

I can run 4K 120Hz with HDR on my LG C4 via HDMI.

 

[PBSanga]

I can run 4K 120Hz with HDR on my LG C4 via HDMI.

Yeah, native works fine, its only HiDPI scaling resolutions above 2560*1440@100hz that won’t work.

 

[matbard]

Just a question: can I run an M4 Pro Mac Mini with a 27" FHD 480hz gaming display?