4K 144Hz over USB-C from MacBook Pro?

I have a fairly new 16" MacBook Pro and two 4K Spectrums on the way. I’d love to get 4K/144Hz video on each Spectrum. The USB standards are super complex and I have absolutely no clue how to determine whether what I’m looking for is possible and if it is, which cable I should buy to make it happen.

Some USB-C cables (such as this CableMatters unit from Amazon) claim to support 8K @ 60Hz, so theoretically should support 4K at a higher framerate. But that cable is only USB 3.2 Gen 1 supporting only 10gbps. That obviously doesn’t add up at all – I’m fairly certain 4k60 doesn’t even fit in 10gbps. Other USB 3.2 Gen 2x2 cables I’ve found note support for 20gbps transfer rate, but only 4k60.

Ideally I’d like 2m/6’ cables but 1m will work fine. Does anyone know offhand which cables, if any, I should be looking for?

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Theoretically what you’re looking for is something that supports HBR3 data rates for DisplayPort, such as Apple’s Thunderbolt 3 cable, but obviously there should be cheaper cables out there that do the same trick. Seems really hard to google for HBR3 without finding USB-C to DisplayPort adapters though, so I can’t point at particular cables. DisplayPort 1.4 and DSC would be other keywords to look out for, although perhaps that doesn’t refer to data transfer speeds. You can pretty much assume that Thunderbolt (3 or 4) cables are going to be fine, although they’ll be limited to 0.8m length due to signaling requirements.

I’m also not the expert to listen to - that would be Benson Leung who sometimes answers questions on USB-C subreddits, perhaps you can find out something there. One thing to keep in mind though is that DP Alt Mode is unidirectional, meaning it has theoretically twice the bandwidth compared to USB data transfer modes, and also it’s a different signaling protocol. And USB 3.2 Gen 1 is only using half the high-speed data lanes, the other half goes to DP Alt Mode if shared on the same cable. If expanding to full DP Alt Mode on all 4 high-speed data lanes and not sharing with data, you can get much higher throughput. DSC doubles the effective bandwidth for video signals from 4K/60Hz to, er, 4K/120Hz or 4K/144Hz or so, if using all lanes. (That’s also why you have to choose between USB 2.0 speeds + 4K/144Hz, or USB 3.0 speeds + 4K/60Hz. USB 3.0 being USB 3.x Gen 1. You can’t have USB 3.2 Gen 2 + DP Alt Mode on the same cable.)

So the limitations of USB 3.2 Gen 1 data transfer speeds don’t necessarily apply, don’t ask me about the exact bandwidth numbers though. There are some AnandTech articles from 2012 or so that helped me understand more about it before I forgot it again.

If it supports 8K @ 60Hz, I’m going to say you’ll be fine. I’d suggest to get a second opinion though! Or wait for the neon red cable that Eve was going to offer to Spectrum customers.

Also, your Cable Matters cable is listed as Gen 2, which means it has all four high-speed lanes rather than just two. I’m almost certain that this will do just fine.

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Are you sure your macbook pro GPU can handle that?
Mine runs hot from just one 4k 60hz monitor.
Well it’s a few years old but still.

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Company machine, I couldn’t care less if it’s not happy about doing it as long as it does it! I used to 2 x 4k60 via a Thunderbolt 3 dock and HDMI outputs, but with Spectrum I’m eliminating the TB3 dock from my setup.

@jpetso: Super informative, thank you for all the details! I guess HBR3 is the key word I was missing. I’ll use that in searching Amazon next.

I stopped by Best Buy and picked up a couple of these cables since they were the best available. They’re…interesting. On one of my Spectrums I’m getting 4k60 (and no way to change the refresh rate afaict). On the other I’m only able to get 4k30. Puzzling… Anyone have any ideas?

The good news is my plan to use Spectrum as a psuedo-KVM switch is going off without a hitch! All my USB accessories are working just fine.

Edit: I found the 60Hz toggle somehow (option clicking “scaled” in Display, enabling “low resolution” options, then selecting one of the low res options gave me a refresh rate drop down box, and switching back to the non-low res version of my desired scale res retained the 60Hz selection). Still no 144Hz options though – unclear whether that’s a cable, monitor, or MacBook problem.

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Ah yes, in order to get 4K/144Hz, your laptop also needs to support DisplayPort 1.4 with DSC. The older 1.2 protocol version doesn’t have DSC, so it can only get up to 4K/60Hz even with full monitor and cable support. Check your MacBook specs.

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This is a 2019 16" MacBook Pro. I can’t find mention of DSC in Apple’s technical documentation but I’m nearly certain it supports DSC as it supports Apple’s 6K Pro Display XDR plus using it as a hub.

Possibly relevant for MBP DSC support. Also, the most relevant AnandTech article for reference.

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Found that thread as well. I’ll try with my other MacBook, which is still on Catalina and see what happens.

[Edit: just tested, seeing the same limitation from my other MacBook Pro on Catalina. So the cable seems to be the most likely culprit to me for now. Will order something from Amazon and report back when it arrives.]

On Amazon I’m seeing many cables billed as 4k60 capable specifically. Some of them even go as far as to say they only support 2k144, such as this one. This seems odd… Firstly, if it supports 4K60 it should support 2k up to 240Hz, correct? And secondly, are there different levels of support for DP-Alt mode? Or perhaps they’re saying the cable supports DP 1.2/1.3 rather than 1.4?

FWIW I have one CableMatters Thunderbolt 4 cable that claims to support everything under the sun and one Godspin Type-C cable on the way to test. The former will almost certainly work, but at nearly $60 it’s not ideal and TB4/USB4/etc support is obviously overkill. The latter says it supports dual 4k60 or single 5k60, which implies it must at least be capable of 4k120 but we’ll see.

Fingers crossed! I’ll update on Thursday when they arrive.

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My understanding is that the cable is responsible for the signaling quality, and Gen 2 capable cables should be sufficient here, whereas DP 1.x is a concern between host (laptop) and monitor. As for the 4k60 label, I could imagine that they’re being conservative by advertising only without DSC. But yeah, finding technically accurate information as opposed to broad use cases is a pain.

Good luck with your cables!

Nice topic! Please, keep posting updates on your findings, I also have an MBP 16" and would love to get 144hz.
I asked the Eve team about it before and @Lore_Wonder replied that he was able to get 144hz on M1 Air with USB-C single cable, but MBP 16" worked only on 60hz.

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Cables have arrived, as have more learnings.

Firstly: it seems the quest to get 4k/144Hz over a single cable has been thwarted by some combination of MacOS 11 (Big Sur) and my 16" MacBook Pro. Neither the CableMatters nor the Godspin Type-C cable is able to drive my corporate machine on Big Sur at 4k/144Hz. This threw me for a loop because with another 4k/144Hz monitor I had, I’m certain I saw a different 16" MBP running at 4k144.

I went hunting and found a USB-C to DisplayPort 1.4 cable in my cable box and hooked it up. No dice, still only 4k60 from my corp machine. However, after seeing the threads about Big Sur breaking DSC I figured I’d double check with my other 16" MBP which is still running Catalina. Lo and behold, with a 16" MBP running Catalina using a USB-C to DisplayPort 1.4 cable I found the promised land: MacOS at 4k 144Hz. I checked with the new Type C cables on the Catalina machine as well, and no luck there: still 4k60 at best.

Even if my corporate laptop could send 4k144 over that USB-C to DisplayPort cable, that setup wouldn’t work for me because 1) I need the DisplayPort for my other PC and 2) I want Spectrum’s USB hubs connected to both computers. So alas, I will resign myself to 4k60 for work purposes until I’m up for a refresh and maybe by then Apple will make HFR-friendlier laptops.

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What a great finding :star_struck:! I knew I didn’t upgrade to BigSur for a reason!

Yea, I agree. For me probably the 3rd thing would be - 3. The single-cable solution was one of the main selling points to me (hub + laptop charging).

Anyway, thanks for sharing @zachr !

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Excellent research! This should come in handy for a lot of users.

So then, this is confirmation that the MBP’s USB-C port can output 4K/144Hz (on Catalina, or if Apple decided to fix it in the future) but the Spectrum messes something up on its own USB-C port. That’s something Eve should look into and try to fix, possibly with a future firmware update. @Lore_Wonder, any insight?

Stupid question, but you did make sure that the USB bandwidth setting on your Spectrum OSD is set to 144Hz @ USB 2.0 as opposed to 60Hz @ USB 3.0 speeds? Not sure which one Eve set as default.

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I’m not sure this is the right takeaway. I suspect the MBP is only capable of 4K/144Hz over a USB-C to DisplayPort cable specifically. I don’t remember where I read this but somewhere I read that the lightning ports on MBP aren’t capable of 4K/144Hz with data. It should certainly be explored, but I’m not confident that it’s possible.

I did! It was 60Hz by default.

Another fun fact: Switching back to 3.1 / 4K60 on the Spectrum when using the Godspin cable above leads to a maximum refresh rate of 30Hz on Spectrum. My other monitor with the CableMatters USB4/Thunderbolt 4 cable is still happily chugging along at 4K60.

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I’m sure there’s a lesson in there somewhere, especially combined with your 3.1 data @ 30Hz experience, but the fact is that USB 2.0 is using its own reserved lanes for data. Whichever DP Alt Mode configuration gets used, it will never access the slow USB 2.0 lanes, only 2 or 4 of the high-speed lanes which USB 3.x Gen 1 or Gen 2 would otherwise use.

I guess it’s theoretically possible that macOS or the particular port hardware on the 16" MBP throws the towel anyway when exposed to any data, despite the cable and monitor dealing with it just fine. Given your USB/DP adapter experience with DSC support and regular USB-C connection without DSC, this may well be the case. It’s pretty weird, but it’s hardware, things often get weird there.

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@zachr

  1. Did you have a chance to test it with Apple Thunderbolt 3 Pro Cable? I doubt it will help, but I heard before that people had different results with Apple’s cables…
  2. Do you have Windows on your Mac (Boot Camp ideally)? Could you run the same tests, but on windows? That way we can be sure where the limitation comes from (hardware or software).
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I haven’t tried Apple’s cable, and frankly with a price tag like that even if it works I’d consider going without because JEEZ. And I thought the CableMatters Thunderbolt 4 cable was ridiculously priced. I suspect that Apple cable would be functionally identical to the TB4 cable though for this use case. Both support HBR3 DisplayPort rates.

I don’t have Windows on my work or personal MBP unfortunately. I’ll consider installing it some time to try it out, but that’s not high on my to do list.

So it turns out that issue was either with the MBP or with Spectrum. I swapped that cable out for the same TB4 cable and that monitor won’t do 4k60 with USB 3.1 selected. 4k30 is the best it will do. The other monitor remains 4k60. I’ve tried several ports on the MBP to no avail.

It’s not the end of the world as I can just swap the USB 3.1 accessories to my other monitor that does 3.1 speeds with 4k60, but it’s definitely a little frustrating. Both Spectrums are on firmware 101 so no difference there.

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Check out the section titled “Things to look out for (macOS)” of this terrific blog post about 4K high refresh rate monitors if you haven’t already!

Just a heads-up, after having used my old USB-C / Thunderbolt cable that got delivered with my LG 27UD88W, today it all of a sudden broke down. I guess it has to do with the rated PD (it was rated for 60W instead of 100W) and quality of the cable in general.

I just replaced it with an official Apple Thunderbolt 3 cable 0.8m (MQ4H2ZM/A
) and this one works perfectly (4K@144Hz + Power Delivery). My local supplier did not have any alternatives in stock, so I can not compare other cables.
Only shame is that it is not available in black.

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Shame that your old cable died! Ouch. Is this from a MacBook Pro? What model, exactly?