Can you get a 4K / 120Hz support from a Thunderbolt 4 port on 2021 MacBook Pro?

HDMI 2.1 changes everything, including what cables are required, and how the data leads are assigned. "48G" HDMI cables required.

"48G" HDMI cables that support this speed are just beginning to appear.

ACTIVE Adapters from DisplayPort, requiring additional power input, are rare and expensive, but Club3D and UpTab appear to be offering them. Uptab warns that their adapter may reach 70 degrees C (about 160F, which could burn your skin).

They also warn that VERY few destination displays are capable fo supporting this high speed and HDMI 2.1 formats, which are completely different from older formats over HDMI 2.0 and earlier.

tl;dr:

4K/120hz SDR can be suported w/ DP 1.4 (@ 32 Gbps)

4K/120hz 10-bit HDR cannot be supported (since software limitation from Apple AND thunderbolt @40Gbps is slower than HDMI 2.1 @ 48Gbps)

My set up is MB Pro 2021 output to LG Oled CX 4K 120hz tv. I bought USBC dp1.4 dongle out from MB then HDMI 2.1 end output from tv with do 1.4 on other end. Connect to dongle from MB. Configure display pref in mac and click on scaling and show all resolutions. I was only getting 120hz on the 1440hz low resolution. As soon as you choose any higher resolution it only gives you 60hz. Apple would have to do a software update. Don't think it's a hardware issue. Thunderbolt 4 should allow 4K 120hz

It is definitely a fact that MacOS is holding us back with getting 4k120 and is not "unfounded". It works fine in windows on the same machine. the moment you switch to MacOS it stops working.

The above statement is incorrect on many levels with regards to HDMI being the issue instead of Apple being the issue.

• 4k 120hz 10 bit HDR 444 only requires 40Gbps, not 48Gbps
• The HDMI 2.1 inputs on LG OLEDs only go up to 40Gbps, proving that they can handle that smaller bandwidth
• PC, Xbox, etc, all can get a 4k 120hz 10bit 444 HDR signal through 40Gbps no problem, only MacOS can't
• MacOS won't even get 60hz 4k HDR 444 through, which only requires 20Gbps

The problem is 100% Apple - they need to prioritize this as the number of users that want to connect a PC to their TVs properly is going up exponentially

Why are these responses absolutely useless? The question is simply, what is needed to output 4k 120hz from the mbp?

According to notebookcheck.net, "In order to enjoy the fluidity of 120Hz on external displays and monitors, users will have to utilize one of the Thunderbolt 4 ports and an according USB-C to Displayport cable (from US$17 on Amazon), which should enable video output at 4K and 120Hz." - https://www.notebookcheck.net/Apple-s-new-2021-MacBook-Pro-only-comes-with-an-HDMI-2-0-port-which-cannot-output-4K-at-120Hz-on-an-external-display.574461.0.html

However, I can't vouch for what they say, and they again say "should", which means not verified, thus why I'm here to see what apple will say before I waste money on a 120hz monitor that I can't output 120hz to...

Not at 444, which is the requirement when dealing with computers instead of video. Try using your computer for a few minutes with 422 instead of 444 to get a sense of what I'm talking about - it's almost unusable. All sharpness immediately disappears and text becomes torture to read

Which monitor? As far as I know, it will only work if the monitor supports DSC. TB4 to HDMI 2.1 on my CX just give me 4k 60hz.

MannyNYC,

It looks like the MacBook Pro supports up to 60.00Hz refresh rate. You can learn more here: Use an external display with your MacBook Pro & Set up and use Apple Pro Display XDR

Have a great day.

Hi MannyNYC,

I'm not too sure if you can get 120Hz at 4k. The best way to test this (if possible) would be to purchase your desired monitor, test it with your Mac, and if you cannot get 120Hz, return it for a full refund.

That said, I think Macs are limited to outputting 60Hz regardless of what the quality is. I could be wrong about this though.

geeksogen--

you are correct that HDMI 2.1 offers higher bandwidth.

Mac Notebook computers offer only HDMI 2.0 directly, and ThunderBolt/USB-C/DisplayPort Dual Mode only supports, at best HDMI 2.0 (HDMI 2.1 has been proposed, but does not appear to have been approved yet)