2020 13" MacBook Pro - i5-1038NG7 / Iris Plus Graphics iGPU / 16GB RAM / 512GB SSD
EDIT: With the May 2020 Windows 10 update that was released today, the below installation steps are almost certainly unnecessary. Updating to Win10 2004 (OS Build 19041.264) should be plug-and-play. I enabled all of the previously disabled devices in Device Manager and it seems to work without a hitch. eGPU works with both hot & cold plug so far.
This section is convoluted, since it required some troubleshooting. These are the steps I took, but they can probably be done in a more efficient order. I will look to update this once I confirm that a different order works better. Limited testing has been done so far but I wanted to get this up ASAP, as others were having the same issues. Originally adapted from guides by @itsage and @andygev35
1. Disconnect eGPU
2. Install Windows 10 1903 V1 via Bootcamp Assistant.
3. Disable Windows automatic updates (I just paused updates but need to apply permanent disable)
4. Install Bootcamp package
5. Install KB4512508 update from https://www.catalog.update.microsoft.com/Search.aspx?q=KB4512508
7. Download the latest version of DDU
8. Reboot into safe mode
9. Go to Device Manager
10. Disable FaceTime Camera, top two PCI express Root Ports and bottom PCI express Root Port, Bluetooth Adapter
11. Go to where you downloaded the DDU application and double-click on it. This will extract DDUinto its own folder. Go to that folder and double-click Display Driver Uninstaller. When the settings dialog appears, enable EVERY OPTION under AMD and Nvidia. MOST IMPORTANTLY, enable "Prevent downloads of drivers from Windows Update" at the bottom.
12. In "Select Device Type" drop-down, select GPU
13. In "Select Device" drop-down, select Nvidia
14. Select "Clean and DO NOT Restart." Once complete, don't exit out of DDU
15. In "Select Device" drop-down, select AMD
16. Select "Clean and Restart"
17. Once back at the Windows desktop, connect eGPU to top right USB-C port, closest to power button. I had and external display connected to the GPU.
18. Download newest NVIDIA drivers from their site. I downloaded GeForce Experience with the drivers
19. Install and reboot
20. Presto, nothing happens. This is where the guide is less of a guide, and more of a story of how I got it to work.
21. Shut down the computer and unplug the eGPU. Also unplug any external displays connected to the GPU
22. Boot back into Windows. Once at the desktop, plug in the eGPU to the top right port without the external display connected to the GPU
23. Go to Device Manager
24. Disable PCIe Root Port #1 - 38B8 (you'll lose wifi). At this point, if everything's working, you may hear your GPU fans spin down to idle, signaling that the eGPU has successfully connected.
25, Plug in external monitor to GPU. It should now work.
26. Re-enable PCIe Root Port #1 - 38B8 to get your network connection back
27. Enjoy your eGPU!
To be updated. I set the graphics preference to High Performance within the NVIDIA Control Panel options in the Windows Graphics Settings.