Color banding/gradient display glitch in Catalina RX 580

[TheJMan36]

Since upgrading from Mojave to Catalina 10.15.7 I've noticed banding in my gradients around the UI and even in Youtube videos. I tried the Hackintool fix in this thread but no luck:

<< Solved >> - Forcing RGB mode for problematic displays

Is that related to the driver of RX 580? Those don’t happen at all on Windows. Yes, it tells macOS which driver to use.

www.tonymacx86.com

The best I can get things looking is with SwitchResX and enabling the "millions of colors" instead of "billions of colors" option. But there is still some banding especially when night shift is enabled.

I'm using an HDMI port on a Sapphire RX 580. Everything looked perfect in Mojave. Attaching some screenshots and my Clover folder maybe there's some setting in my config.plist causing this?

**The banding isn't showing up as badly in my screenshots for some reason, you'll have to take my word that it looks way worse in person.**

 

[Bustycat]

Please try the new method without building from Hackintool.

 

[TheJMan36]

I thought that was for Big Sur only?

EDIT: I see now you recommend to try that first for Catalina. Trying it now.

 

[Bustycat]

I thought that was for Big Sur only?

EDIT: I see now you recommend to try that first for Catalina. Trying it now.

Not sure but it’s worthy to try as it doesn’t do anything to /System.

 

[TheJMan36]

Ok so that seems to improve the banding a good amount. It's not perfect but it's workable now. In Preferences->Displays it now shows [monitor name] - forced RGB mode EDID override.

I'm also no longer able to modify the contents of System/Library/Displays/Contents/Resources/Overrides. I thought I might try copying the file generated by terminal to that directory too.

It also changed my framebuffer depth from 24 bit color to 30 bit color.

 

[Bustycat]

Ok so that seems to improve the banding a good amount. It's not perfect but it's workable now. In Preferences->Displays it now shows [monitor name] - forced RGB mode EDID override.

I'm also no longer able to modify the contents of System/Library/Displays/Contents/Resources/Overrides. I thought I might try copying the file generated by terminal to that directory too.

It also changed my framebuffer depth from 24 bit color to 30 bit color.

The new method overrides the same thing in /System. On Big Sur attempting to edit files inside /System is dangerous.

 

[TheJMan36]

I just don't understand why doing this prevented me from modifying the contents of /System/Library?

 

[Bustycat]

I just don't understand why doing this prevented me from modifying the contents of /System/Library?

Big Sur introduces the APFS snapshot for /System, making modifying drastically much difficult and risky.

 

[TheJMan36]

I'm using Catalina.

 

[Bustycat]

I'm using Catalina.

You still have to unlock the Gateway Keeper via Terminal or Hacintool if you want to write to /System in Catalina.