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Comment by Falell | Hacker News Reader

It's correct in my experience. My mac refuses to recognize 2 independent monitors in the following setup: laptop -> USB-C -> dock -> 2x 1440p@144hz Displayport monitors. Supposedly this is because Apple doesn't implement the entire Displayport spec, I don't really know the details. My windows laptop handles this particular setup just fine, but forgets one of my displays at work every so often. It's a mess.

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> Supposedly this is because Apple doesn't implement the entire Displayport spec, I don't really know the details.

I can see that. I had 2 27" 4K HDR 144Hz monitors that worked fine in Catalina. Big Sur and Monterey, they do not: they'll do 95Hz SDR and 60Hz HDR.

If on my screens I change DisplayPort mode from 1.4 to 1.2, they'll do better (120Hz SDR). So something in Big Sur broke DP 1.4. And Apple doesn't care, because there have been hundreds of bug reports on it ever since the Big Sur betas and it's still broken as of Monterey 12.0.1.

I guess Apple's philosophy is "we don't care if you don't have a Pro Display XDR" (and I say that as someone who owns one).

Correct, Big Sur broke DisplayPort above a certain bandwidth, but only on Intel Macs as I understand it.

https://discussions.apple.com/thread/252174979?page=1

https://egpu.io/forums/mac-setup/4k144hz-no-longer-available...

I have to use SwitchResX to define a custom resolution (95Hz), otherwise my gaming monitor won't go above a sad 60Hz.

Meanwhile, Linux runs perfectly on the same setup all the way up to 160Hz. Yet another place where Linux has fundamentally better hardware support than Mac.

Interesting. My M1 Max laptop arrived the other day. I might have to try it.

Even Catalina wouldn't support my displays at 160Hz, only 144Hz.

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