I have a monitor that support 4K/120HZ with an HDMI 2.1 input. If I get an adapter to connect to the TB4, will that get me to 4K/120Hz? The technical spec isn't clear as to whether that would work.
I have a Gigabyte M32U which supports 4K up to 144 Hz. I just tested it and that worked on my Mac but I put it back to 120Hz as I really can't tell the difference between 144Hz and 120Hz but 120Hz to 60Hz is very noticeable to someone like me who reads content as they scroll. It makes for a much better experience.
I connect by using a CablesMatter Usb-C to DP 1.4 adapter to connect to the DP 1.4 port in the monitor. I didn't try converting the USC-C to HDMI 2.1
4K at 60 Hz with High dynamic range is supported by HDMI 2.0, which is featured on the direct HDMI output ports on M1 Pro and M1 Max models that have HDMI output ports.
All the people I've seen test this has not gotten it to work. It works when going to displayport but not HDMI. Ive seen speculation that this is because MacOS does not support necessary features of HDMI and it is a MacOS limitation. The speculation is based on earlier similar testing where if you used bootcamp you could go this route.
if you look in this article about DisplayPort Dual-Mode, you will see that there are technical issues converting to HDMI at high speeds and high resolutions.
https://en.wikipedia.org/wiki/DisplayPort#DisplayPort_dual-mode_(DP++)
The conclusion that "MacOS is holding out on you" is unfounded.
These interfaces are switching on the hairy edge of maximum switching speeds of ordinary digital logic. 40 GigaHertz over four lanes means each signal could be changing states at 10 Gigahertz, or 0.1 nanosecond -- that is very fast.
Can you get a 4K / 120Hz support from a Thunderbolt 4 port on 2021 MacBook Pro?
