@b563052622, Interesting that it works in 11.0.1 for you, I never managed to get that. But sadly I must report that my situation did not improve with this 11.2 Beta. I still have to try and reset everything related to the display, maybe some old config would propagate between updates, but it is very likely it is not that...
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@red_epicness, Nither for me. It didn't work in 11.2 beta. Have to format the disk to downgrade to mac os 11.0.....It's most likely Apple has stop supportting monitor with high resolution and freshrate in the future?
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.@b563052622, I highly doubt they would stop supporting something like that without explicitly warning users before upgrading... Still most likely a bug with new drivers...
To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.
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Yep. I can confirm too that the issue is unchanged in Big Sur 11.2 beta 1 as well. I updated my radar to report that.
I did find a reasonable compromise on the Apple Support Forums though. If your monitor supports different versions of DisplayPort, downgrading to DisplayPort 1.2 seems to resolve it. You won't get the full frame rate as DP 1.4 (My 4K monitor could only hit 80Hz on DP 1.2), but if this problem was explicitly impacting your productivity, this will at least fix that. 
Hey folks! Happy New Year! Apple just released Big Sur 11.2 beta 2.
I've unfortunately had to pack my 4K monitor away since I'm in the middle of a move, so I can't test to see if this issue is fixed myself. But I'm really itching to know. If anyone else could give it a try, I would be super thankful.
Thanks!
I don't know if 11.2 beta 2 fixes the issue, but I have found a good-enough-for-right-now solution.
With the app EasyRes (free on the Mac AppStore), you can get up to 4K/120Hz if you switch from 1.4 (DSC) to normal 1.4 in the LG OSD. For now, this is fine. I hope Apple issues a fix soon. Maybe they already have with 11.2 beta 2, who knows.
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I'm on the released version of Big Sur @tim, and on the exact same monitor as you, unfortunately I don't see any way to make it up to 4k/144hz still.
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.I'm on the released version of Big Sur @tim, and on the exact same monitor as you, unfortunately I don't see any way to make it up to 4k/144hz still.
He's saying the newest beta might have fixed it (we have no idea), but the latest official release we know doesn't solve it.
To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.
.Apple just released Big sur 11.2 RC1. Has anyone tried that out?
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.Woah! The RC is out?! That was fast! Sadly I'm in the middle of relocating at the moment and my 4K monitor is still in transit. When it arrives, I'll try it out as soon as I can. Until then, if someone else can give it a try, I am super super burning to know if it's fixed at this point. 🤣
I'm on the released version of Big Sur @tim, and on the exact same monitor as you, unfortunately I don't see any way to make it up to 4k/144hz still.
Oh cool. Thanks John. Good to know it's not just me at least. If you want, please consider upgrading to the 11.2 Release Candidate and try it out on there.
Thanks!
-TiM