Mac mini 2020 with eGPU attached fail to display while switching to MacOS
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Mac mini 2020 with eGPU attached fail to display while switching to MacOS  


New Member
Joined: 8 months ago

Hey guys I'm new to here, hope to learn from here more!

Here's the situation, I got this build:

-Mac mini 2020 with i7-8700b in 10.15.4

-Razer Core X Chorma

-Radeon VII

It works fine under MacOs and Windows right now. My Windows build are 1909 and have use the temporally fix by replacing the pci.sys file from 18362.295 ISO to prevent error 12. Now I'm connected the monitor through my eGPU's DP solely, with the TB3 always attached.

When I reboot under MacOS the eGPU works fine. Reboot under bootcamp works fine also. Reboot from MacOS to bootcamp works ok too, but it will fail when I reboot from bootcamp to MacOS.

After I choose to reboot to MacOS, I can see the screen is lighted, but I don't see any pictures output. I've only experiences once that successfully reboot from bootcamp to MacOS, other times are just more than 10 minutes wait and nothing happens. I can unplug the TB3, boot up by HDMI using iGPU first and then hotplug the eGPU as a workaround, but it just simply unconvinced. Hope to have some more elegance way.

How can I fix this problem? Have anyone has the same issue?

Mac mini 2020 with i7-8700b 32G RAM
Razer Core X Chorma
Radeon VII

Mini i5
Honorable Member
Joined: 1 year ago


You don’t need to unplug/replug the TB cable.

Select “boot into Mac OS”.

Wait for the Windows screen to disappear.

Turn off your Core X.

Wait one minute or so.

Turn on the Core X.

Log in to Catalina.

Also, download Macs Fan Control to better cool your i7. It allows my i5 to  sustain turbo boost speeds of 3.9 GHz whenever I try CPU-only rendering.

I’m curious how high a clock speed the i7 can sustain when using this helpful utility. 

2018 Mac Mini i5 / 6-core 3.0-4.1 Ghz / 32GB / 256GB / Intel UHD 630 / PowerColor Gaming Station / PowerColor dual-fan RX 5700 XT / Mac OS 10.15.6 Catalina / Windows 2004 😏 / Dual LG 27" 4K displays