‘18 mini w/Vega 64 Core X eGPU issues

anaudiopro

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So I got my new mini today and noticed something bizarre right off the bat when using the Vega 64 in the Core X eGPU. It is rather peculiar too. Transparencies exhibit bad color banding when hooked up to the eGPU via DisplayPort. As soon as I hook up via HDMI it is all smoothed out. If anyone has this setup, test it for yourself. Open up Safari and just look at the transparency of your wallpaper behind it. It won’t be smooth it will be pixelated. Hopefully someone can help me figure this out.

 
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KennethS

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Jan 4, 2011
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I have the same setup attached to an LG 27UK850 and I don't think I am having this. I will await to see your photos to make sure I understand what you are seeing/reporting.
 

anaudiopro

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I have the same setup attached to an LG 27UK850 and I don't think I am having this. I will await to see your photos to make sure I understand what you are seeing/reporting.
I am using 27” BENQ 2560x1440 displays. When hooked up to the Core X eGPU via DisplayPort open up Safari. Don’t go to any website. Leave it so that you can see through the transparent Safari window and see your wallpaper. Drag the Safari window around your desktop watching the wallpaper through the transparent Safari window. You should see that the transparent effect is all pixilated and not smooth. If you aren’t seeing it then try using HDMI instead of DisplayPort and then maybe you’ll see the difference.
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I have the same setup attached to an LG 27UK850 and I don't think I am having this. I will await to see your photos to make sure I understand what you are seeing/reporting.
Another anomaly I noticed is when I restart my machine or boot up from power off I see a red square for a split second before it goes to the login screen. Do you see this? Again, I only get this when connected via DisplayPort. I’ve tried many different cables so I know it’s not my cable.
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I have the same setup attached to an LG 27UK850 and I don't think I am having this. I will await to see your photos to make sure I understand what you are seeing/reporting.
How are you connecting your LG display to the Vega 64 and eGPU?
 

KennethS

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Jan 4, 2011
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Core X is connected to my mini with the lightning cable that came with the Core X, and my VEGA 64 is connected to my LG monitor with a DisplayPort cable that came with the monitor. I do get a red box when re-starting the mini, but it doesn’t concern me and I haven’t focused on it.
 

anaudiopro

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Here is a video to demonstrate exactly what I am talking about:

 

th0masp

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Mar 16, 2015
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That looks like banding - not pixelation - what you have going on there.

Are color bit-depth settings diffferent between each of these GPUs? Perhaps there are driver settings to adjust on the external card? Could the color profiles in Preferences/Monitor be responsible for some of this?
 

anaudiopro

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That looks like banding - not pixelation - what you have going on there.

Are color bit-depth settings diffferent between each of these GPUs? Perhaps there are driver settings to adjust on the external card? Could the color profiles in Preferences/Monitor be responsible for some of this?
I am at a loss. I tried many different color profiles to see if any of them would fix it, and nothing does. I wouldn't have any clue how to adjust driver settings for this Vega 64. Any help anyone could be would be appreciated!
 

th0masp

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Mar 16, 2015
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I am at a loss. I tried many different color profiles to see if any of them would fix it, and nothing does. I wouldn't have any clue how to adjust driver settings for this Vega 64. Any help anyone could be would be appreciated!
Well, what is it looking like on the monitor side? Any settings you can access for the display port connection? Perhaps you can specifiy the input color format there and make sure it's set to RGB? Or at the least ensure that it uses the same settings as the other connection.

I would normally put it down to driver issues in relation to that blur effect but I assume the Vega 64 is support well enough in mac OS.
 

anaudiopro

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Well, what is it looking like on the monitor side? Any settings you can access for the display port connection? Perhaps you can specifiy the input color format there and make sure it's set to RGB? Or at the least ensure that it uses the same settings as the other connection.

I would normally put it down to driver issues in relation to that blur effect but I assume the Vega 64 is support well enough in mac OS.
I have tried all the possible settings I could on the display itself and nothing fixes the banding. And you are correct, it is color banding not pixilation, almost as though the bit depth is dropped down or something but it isn't. This is very upsetting. What I do not understand at all is why it doesn't act the same way via HDMI. Could I have a bad video card or eGPU box?

So I just tried a simple test of looking at test images to see banding and you can even see it there when using the DisplayPorts on the Vega 64. It is very subtle, but it is there.

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1B60635D-1646-4BE2-AC63-03AD47828070.jpeg
25AB7C4E-0767-45AD-B97B-0F8A0D81BE70.jpeg
 
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th0masp

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Mar 16, 2015
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It's possible that your monitor is using a different mode when connected via HDMI, I have seen examples of monitors incorrectly stating their capabilities, resulting in different looking output on a more 'capable' protocol.

If there are not settings to adjust anywhere you could look into hooking up your eGPU over HDMI. If it does not have a HDMI out then there are adapters and display splitters that might come in handy.
 

anaudiopro

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It's possible that your monitor is using a different mode when connected via HDMI, I have seen examples of monitors incorrectly stating their capabilities, resulting in different looking output on a more 'capable' protocol.

If there are not settings to adjust anywhere you could look into hooking up your eGPU over HDMI. If it does not have a HDMI out then there are adapters and display splitters that might come in handy.
The problem is the Vega 64 only has one HDMI out. I need two. You don’t find it at all odd that everything looks fine when using HDMI but DisplayPort has bad color banding? Could the Vega 64 have bad outputs? Or could it just be that the Vega 64 is reporting improperly to the BENQ display? I just wish I knew what the culprit was.
 

zandorf

macrumors member
Oct 24, 2013
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My LG monitor by default ran DP 1.1 protocol. Configuring it to DP 1.2 enabled 10-bit colors which helps banding. Maybe this is a clue for you.
 

anaudiopro

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My LG monitor by default ran DP 1.1 protocol. Configuring it to DP 1.2 enabled 10-bit colors which helps banding. Maybe this is a clue for you.
I have the BENQ set to DP 1.2. I’ve tried both settings and the banding is still there.
 

anaudiopro

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I have a 580 card I am going to try here in a minute. If it is still doing the same thing then it either has to be the Core X or the BENQ monitors and the way they are seeing DP, even though none of that makes any sense. I’ve been using these monitors with other Macs with no issues at all. I will report back.
 

anaudiopro

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Have you tried a direct TB3>DP cable from the mini?
Yes I have and it works perfect. Also just tried a RX 580 card and it does the same exact banding thing using DP and not using HDMI. So I am starting to think that far more people are experiencing this exact same thing than even realize it. If you aren’t looking closely through transparencies you won’t see it. Something is definitely off here.
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Have you tried a direct TB3>DP cable from the mini?
Is there any chance for some bizarre reason that it’s just these BENQ displays when using an eGPU over DP? I’d hate to get rid of these two displays. They’ve been awesome. PD2700Q is the model number.
[doublepost=1545167229][/doublepost]I am getting ready to try another monitor. That is the last variable. If it still does it then everyone using this eGPU setup is experiencing it and just doesn’t notice...
 
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anaudiopro

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I’ve tried 3 BENQ displays and they all do it. I’m getting ready to try a 4K LG. If it does it as well I will be convinced this is an Apple thing and that the issue is there and people aren’t looking. I looked in system report and everything looks like it should. Strange thing is it only seems to affect the color bit depth. The only thing that would remain after all these tests would be the Core X, but how could that cause such a bizarre issue with DisplayPort only?
 

anaudiopro

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I have awesome news to report. Well, not so awesome for BENQ. I switched to LG 4K displays and no more color banding when using DP cables. So far everything is great.
 
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jinnyman

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Sep 2, 2011
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Based on what you've found, only feasable reason would be that Benq monitor's color mode setting is differentiated between HDMI input and DP input.

Before dismissing Benq, try the monitor setup. It should have a built-in color mode setting like sRGB etc.
 

anaudiopro

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Based on what you've found, only feasable reason would be that Benq monitor's color mode setting is differentiated between HDMI input and DP input.

Before dismissing Benq, try the monitor setup. It should have a built-in color mode setting like sRGB etc.
I have tried all the settings within the monitor. Makes no difference. And I tried it on 3 different ones. I’m all in on this 4K LG.
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Based on what you've found, only feasable reason would be that Benq monitor's color mode setting is differentiated between HDMI input and DP input.

Before dismissing Benq, try the monitor setup. It should have a built-in color mode setting like sRGB etc.
As a matter of fact I called BENQ support and they were at a total loss.
 

waterchill

macrumors newbie
Aug 19, 2016
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Please can you also make a video of the screensaver issue? I have already sent all the stuff back.
 

anaudiopro

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Mar 7, 2017
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Please can you also make a video of the screensaver issue? I have already sent all the stuff back.
I’m no longer having any issues at all with the new 4K LG monitors. My culprit was the BENQ displays.
 

waterchill

macrumors newbie
Aug 19, 2016
19
2
And if you connect to eGPU the screensaver arabeske and shell go complete smoothly? No lags no stuttering?