Help! 5K only at 30Hz ? MacMini 2018, Sonnet Breakaway Box 650, Radeon RX Vega 64, LG 34WK95U DisplayPort  

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konzentrat
(@konzentrat)
Active Member
Joined: 2 months ago
Posts: 10
December 29, 2018 8:35 pm  

So I got this setup:

MacMini 2018

Radeon RX Vega 64

Sonnet Breakaway Box 650

LG 34WK95U 34" 21:9 UltraWide 5K2K Display

Now the problem is that I can run the LG Display only at 30Hz somehow when connecting it with DisplayPort over the Vega 64! I use the original LG cable provided with the screen and the original TB3 cable provided by Sonnet.

When I use TB3 directly from the MacMini everything works fine, but the Performance of the Vega 64 isn't used properly when not connected to the display. I am running macOS 10.14.2. Display is set to DisplayPort 1.4

Anyone an idea what is going on?

UPDATE:

Okay, so it happens that I have this whole setup twice :). So I set up the complete exact same setup up today and with the 2nd setup everything works fine with 60Hz!

So I started to change every part of the setup. First I attached the screen from the 1st setup to the the MacMini from the second setup. And there it works with 60Hz!

I ended up checking every combination and found that the MacMini seems to be the problem here. But it is setup exactly the same like the 2nd setup except language is set to in English in the 1st setup and German in the 2nd setup....

I added the Image of the second setup to the original post.

Hmmm... very confusing.

1st setup:

2nd setup:

Mac mini (2018)
Sonnet Breakaway Box 650
Radeon RX Vega 64
LG 34WK95U 34" 21:9 UltraWide 5K2K Display


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theitsage
(@itsage)
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Posts: 3400
December 31, 2018 1:42 am  

Glad to see you get it working at full resolutions. Have you tested if the DisplayPort version on the monitor makes a difference? What about the DisplayPort cable?

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konzentrat
(@konzentrat)
Active Member
Joined: 2 months ago
Posts: 10
January 1, 2019 11:37 pm  

Hi there,

yes I tried the DP Versions. I also switched the DP Cable with the other one which I know is working with the 2nd setup. This didn't help.

The screen works correctly with the second setup but not with the 1st...

This post was modified 2 weeks ago

Mac mini (2018)
Sonnet Breakaway Box 650
Radeon RX Vega 64
LG 34WK95U 34" 21:9 UltraWide 5K2K Display


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joevt
(@joevt3)
Reputable Member
Joined: 1 year ago
Posts: 298
January 3, 2019 5:38 am  

The display connected to the Vega 64 should use DisplayPort 1.4.
The display connected to the Mac mini should be set to DisplayPort 1.2 (over Thunderbolt) or maybe this is not necessary if it's working already. Maybe the display needs to be power cycled - like disconnect everything, turn it on, then connect only the DisplayPort 1.4 cable before turning it on again.

Did you check the OS versions on each of the Mac Minis? Maybe there's a difference in the graphics drivers?

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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konzentrat
(@konzentrat)
Active Member
Joined: 2 months ago
Posts: 10
January 7, 2019 2:55 pm  

So after several attempts I finally managed to reset the SMC (or at least I think I did) and the Hz selection in the display settings wasn't greyed out anymore. So both setups run with 60Hz now.

There wasn't any feedback or restarting of the MacMini when I reset SMC. So I am not 100% sure I managed to and this is the solution. But something happend...

I wasn't able to boot into Target Disk Mode and reset the PRAM & VRAM because there was a Firmware Password set from the IT department and the reset isn't possible (since the new T2 Chip) without the password.

Mac mini (2018)
Sonnet Breakaway Box 650
Radeon RX Vega 64
LG 34WK95U 34" 21:9 UltraWide 5K2K Display


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