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gabrielefx

macrumors member
Original poster
Feb 15, 2020
62
47
On MacOS the Radeon Pro 580X can use two Apple XDR (HDR) 6K displays 6016x3384 at 60Hz or two 5K displays 5120x2880 at 60Hz.

I bought one 21:9 5K display 34WK95U from LG 5120x2160. It' a certified hdr monitor with thunderbolt 3 port.

Well, the HDR mode is not available on MacOS and partially on Windows 10 (TB3 port used)

On Windows 10 (bootcamp) the HDR mode is available only at lower resolutions, for example 3440x1440 with blurry effect because it is interpolated.

On Windows 10 at 5120x2160 enabling the HDR mode the monitor turns black and stucks, I have to unplug the power cord, turn it on again, plug the HDMI cable to select another output of the Radeon 580X and deactivate the HDR option of the second display (tb3 output)

No problems with Nvidia GTX or RTX gpus, the HDR is properly visualized at the maximum resolution.

The Radeon Pro 580X sucks or Apple limited the use of this gpu with non Apple displays. Also it'a a shame I can't use non Apple displays HDR certified on MacOS

regards.
 

Krevnik

macrumors 601
Sep 8, 2003
4,101
1,312
macOS doesn't yet support HDR for external displays other than the XDR. Apple is very late to this particular party.

That's changing in 10.15.4 though: https://egpu.io/forums/mac-setup/prefer-hdr-mode-in-macos-10-15-4-beta/

EDIT: To avoid double-posting, I'll just add:

I am curious how well this works, as I've got an "HDR capable" LG ultrawide too (LG 38GL950G). I'm not expecting much to be honest, as HDR400 is kinda underwhelming in Windows, or I run into games that aren't properly graded and just make everything eye-searingly bright for my workspace calibrated to a "mere" 110 nits. It's more of a mess than on UHD TVs and game consoles, sadly. Maybe Apple will fix that, but they can't even display the SDR Apple TV menu properly when the Apple TV has HDR turned on, and it's been like that for two years.

I'd play with the beta, but with things happening in my neck of the woods, and people like me being strongly advised to work from home until the end of the month, I'm more in a position to wait for the final release than be messing with my home office machines.
 
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Krevnik

macrumors 601
Sep 8, 2003
4,101
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So, I updated to 10.15.4 on my machine just now, and totally forgot HDR support was coming, so I booted into a painfully bright desktop.

Not only did the 580X detect that my monitor supports HDR (38GL950G), but activated it by default on first boot.

Yeah, as I said, Apple’s late to this party, but it’s surprisingly a smooth experience compared to my Win10 machine.
 

gabrielefx

macrumors member
Original poster
Feb 15, 2020
62
47
So, I updated to 10.15.4 on my machine just now, and totally forgot HDR support was coming, so I booted into a painfully bright desktop.

Not only did the 580X detect that my monitor supports HDR (38GL950G), but activated it by default on first boot.

Yeah, as I said, Apple’s late to this party, but it’s surprisingly a smooth experience compared to my Win10 machine.
Thank you.
Is the 10.5.4 a beta version? Are you using a thunderbolt 3 cable?
 

Krevnik

macrumors 601
Sep 8, 2003
4,101
1,312
10.5.4 came out yesterday. MacRumors reported on it.

My monitor doesn’t support Thunderbolt, so it’s connected using a USB-C to DisplayPort cable. The Moshi cable I linked in your other 580X thread.
 
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