2024 MacBook Pro M4 Pro paired with 32in 4K OLED 240hz - refresh rate only going up to 120hz?

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2024 MacBook Pro M4 Pro paired with 32in 4K OLED 240hz - refresh rate only going up to 120hz?

Hi, I recently bought the M4 Pro MBP and I'm trying to pair with my Samsung 32" Odyssey OLED G80SD but cannot hit into 240hz.

I've tried a range of cables (7) from HDMI 2.0 | 2.1, HDMI to USB C DP 1.4 with DSC, DP 2.1 with DSC to USB C, and nothing will get this monitor to go into 240hz.

I bought a secondary Mac just to ensure it was not a faulty device and I've spoken to apple and Samsung technicians and neither are able to give me an answer. I can't rule out anything yet but the fact I bought a 2nd device and multiple cables makes me point to the monitor or apple has a slight bug in software potentially.

Can anyone help or advice out there?

Many thanks

MacBook Pro 14″, macOS 15.1

Posted on Nov 18, 2024 11:11 AM

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Answer 1

Nov 18, 2024 1:31 PM in response to TeeBee73

Data rates faster than 4K at 60 Hz REQUIRE a MacBook Pro 2023 or later, which you appear to have.

To connect via HDMI using ONE cable:

You MUST use the built-in HDMI port, and Adapters are NOT supported. You will be using HDMI 2.1 rules, so discard all the cables that do not meet that spec or are less than certified as HDMI "Ultra" or "48G" or "8K" cables.

There is no official cable length limit. However, all other protocols running at these speeds with this signaling method limit cable lengths to 1 meter or shorter, so it would be prudent to follow suit.

Once you do that, do you have any cable that is EXPECTED to work?

HDMI over ONE cable using 8 bit color appears to support up to 4K at 240 Hz with Display Stream Compression (DSC).

HDMI over ONE cable using 10 bit color appears to support up to 4K at up to 144 Hz, maximum.

You may need to dedicate TWO ports and cables to achieve this refresh rate for 10-bit (HDR) color. Your display has two inputs, but it is not obvious whether it supports the required Picture-By-Picture feature to make this work. If this as all "word-salad" just ask.

DisplayPort:

This resolution is attainable, but tops out at about 98 Hz refresh (10 bit color). Higher refresh rates are not attainable using ONE displayPort cable or adapter, and your display has only one DisplayPort input.

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Answer 2

TeeBee73 Author

Level 1

4 points

Nov 18, 2024 5:03 PM in response to Grant Bennet-Alder

Much appreciated, thanks for taking the time to answer.

So following your guidance I have a Cable capable of meeting the requirements but that's still Caps out at 120hz.

I'm going to purchase another cable in the 1m variant and hopefully see how that goes, and I'll comeback and update.

I'l be happy to get the 240hz working so I can rule out this being a monitor issue.

I'm planning on getting a thunderbolt 5 dock at some point so potentially connect the secondary wire via the dock.

really useful info, thank you!

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Answer 3

Nov 18, 2024 6:14 PM in response to TeeBee73

<<. I'm planning on getting a thunderbolt 5 dock at some point so potentially connect the secondary wire via the dock. >>

That seems [to me] unlikely to improve anything, but do keep us posted!

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