System specs
2018 Mac Mini
3.2 GHz Six-Core Intel Core i7
32gb RAM (from OWC)
1 TB SSD
macOS 10.15.5
Win10 Insider Preview 20150
Oculus VR software
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eGPU hardwareÂ
Sapphire Gearbox + included TB3 cable
Sapphire Radeon RX 5700
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VR hardware
Oculus Quest
PartyLink 5m TB3 cable for PC VRÂ
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Installation stepsÂ
Gearbox:
Updated the Gearbox firmware (in Windows) as detailed here - https://egpu.io/forums/thunderbolt-enclosures/h2d-bandwith-firmware-update-for-sapphire-gearbox-is-available-now - to address the H2D bandwidth issue.Â
macOS:
Plug and play worked fine.
Windows (via Bootcamp):
Couldn't get the eGPU to appear in device Manager, despite installing Windows 1903 iso via Bootcamp (and upgrading it to OS Build 18362.295) and using the revised EFI Bootloader from @goalque - admittedly I almost certainly messed things up here, since I’m clueless about editing the config.plist file.Â
The following Reddit post gave me a viable answer: https://www.reddit.com/r/eGPU/comments/hpixmo/success_with_mac_mini_2020_and_razer_corex_with  (I see now though that this has been a topic of discussion for months now egpu.io). To paraphrase Redditor @dlittlefair1:Â
 Installed the current developer preview of Windows (Win10 Insider Preview 20150) via Bootcamp.
- Booted into Windows, uninstalled the drivers with DDU.
- Plugged the eGPU into the port next to HDMI, switched it on, and installed the drivers from bootcampdrivers.com.
- Shut down, unplugged the HDMI cable from the Mac Mini and connected it to the eGPU.
- Switched on the Mac Mini and switched on the eGPU in quick succession.
- Success - the windows login screen appears, and the eGPU is running (and working well  with games and PC VR).
For Bootcamp VR enthusiasts - once the eGPU was recognised in Windows, it was just plug and play with the Oculus VR software + Quest + PartyLink cable.Â
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Comments
Currently the only way to get Quill (VR storytelling/animation) running on a Mac. The PC VR version of Tilt Brush (VR drawing) also works nicely.