Macbook M2 Max 14" 2023 HDMI 2.1 out doesn't work for high framerate

[Niber]

I have a Samsung s95b OLED TV with a 2.1 HDMI cable, when I plug that into my PC I get 120p 4k HDR, but when I plug that exact same cable into the macbook it just goes into an endless loop of detecting the TV for a second then dissconnecting, over and over again

or.. if I turn off the hdmi 2.1 setting on the TV then it works from the Mac, but then the HDR button dissapears (from the Mac settings) and the framerate goes up to only 60.

 

I've tried with 3 different HDMI cables. I will admit that HDMI 2.1 cables are super finniky, the slightest bit of extra twist on them can downgrade them into hdmi 2.0 specs, but I think that isn't what's happening here.

 

 

[Alex Atkin UK]

31 minutes ago, Niber said:

I have a Samsung s95b OLED TV with a 2.1 HDMI cable, when I plug that into my PC I get 120p 4k HDR, but when I plug that exact same cable into the macbook it just goes into an endless loop of detecting the TV for a second then dissconnecting, over and over again

or.. if I turn off the hdmi 2.1 setting on the TV then it works from the Mac, but then the HDR button dissapears (from the Mac settings) and the framerate goes up to only 60.

 

I've tried with 3 different HDMI cables. I will admit that HDMI 2.1 cables are super finniky, the slightest bit of extra twist on them can downgrade them into hdmi 2.0 specs, but I think that isn't what's happening here.

Sounds a lot like the HDMI problems the M1 Mac had trying to get HDMI 2.0 to work.

Have you tried an optical cable?  I've started using those even for short lengths to get around the cable lottery.

[Niber]

9 hours ago, Alex Atkin UK said:

Sounds a lot like the HDMI problems the M1 Mac had trying to get HDMI 2.0 to work.

Have you tried an optical cable?  I've started using those even for short lengths to get around the cable lottery.

No i haven't tried optical, I'm tempted to but they are quite expensive and would take so long delivery time where I live.

 

if a PC were acting up with hdmi 2.1, I would simply have set the framerate lower, so that at least I could experience 60fps hdr (or as low as 24), but the mac won't let me because it disconnects the second monitor before I have a chance to change the setting

[Alex Atkin UK]

4 hours ago, Niber said:

No i haven't tried optical, I'm tempted to but they are quite expensive and would take so long delivery time where I live.

 

if a PC were acting up with hdmi 2.1, I would simply have set the framerate lower, so that at least I could experience 60fps hdr (or as low as 24), but the mac won't let me because it disconnects the second monitor before I have a chance to change the setting

Yeah that's frustrating, as like you said its a good way to tell if its a bandwidth issue with the cable which can happen on one device and not another due to different power levels.  I get the feeling the problem with the M1 was possibly not putting out enough voltage or current so a marginal cable loses the signal, which also depends on how sensitive the display is at picking up that signal too.

 

I've been through so many HDMI cables over the years due to signal problems.

[Niber]

On 6/15/2023 at 9:08 AM, Alex Atkin UK said:

Yeah that's frustrating, as like you said its a good way to tell if its a bandwidth issue with the cable which can happen on one device and not another due to different power levels.  I get the feeling the problem with the M1 was possibly not putting out enough voltage or current so a marginal cable loses the signal, which also depends on how sensitive the display is at picking up that signal too.

 

I've been through so many HDMI cables over the years due to signal problems.

Thank you that turned out to solve the issue. I'm not sure why the other cable worked on PC but not for the Mac, but in either case an optical cable solved it, it was just a bit difficult to source where I live