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by FireBeyond 821 days ago
There's also cases where (shockingly to some) Apple just doesn't care.

I'm still more than bitter, after buying some nice 27" 4K HDR 144Hz monitors that Apple actively broke (and may still be broken) Display Stream Compression 1.4 for the Pro Display XDR.

When it was released, there were questions about how Apple was managing to drive that display.

Well, the answer is because they absolutely nerfed/bastardized DSC 1.4 from Big Sur to make it happen with some proprietary magic: those same screens could now only be driven at 60Hz in HDR10 or 95Hz in SDR.

Proof in the pudding was that my monitors (LG27GN950-B) actually allowed you to change the advertised/supported DSC version, and when I "downgraded" the monitors to DSC 1.2, performance actually improved, and allowed 120Hz SDR and 95Hz HDR.

This happened with many many users, across many screen types.

And if you downgraded to Catalina? Boom, back to 144 Hz.

Apple studiously ignored it, and may still be. They simply don't care if you're not using an Apple display.

1 comments

Btw, do you mean you downgraded DP to 1.2? I think there isn’t a DSC 1.4 (only DP 1.4 which has DSC 1.2, and DP1.4a with DSC 1.2a).

Do you have any more info/links about this? I’m curious, since I do have a Pro Display XDR, and I’ve been trying to understand for some time how exactly it’s able to reach its bandwidth, which is definitely a rabbit hole.

Apologies, you're right. DP 1.4 - just looked at the manual (for the LG 27GN750-B, though I know that many other monitors were affected). Has been a couple of years now.

Ironically, I too, moved to the XDR.

Downgrading to DP 1.2 improved the display options from DP 1.4.