Boot Camp eGPU Setup Guide - Windows Gaming with Macs
I have a Mac mini Late 2018, Razer Core X, Radeon RX 5700XT, using Big Sur. One monitor, connected through HDMI on the mac and through DP on the Razor. (have to switch input port on the monitor when using the Razor)
Succeeded in getting it to work with Windows10 20H2 (OS Build 19042.631), latest AMD drivers.
I used aa15032261 's automated EFI replacement, and followed his instructions. The TB3 for the Razer is in the leftmost TB3 port now.
There are some peculiar things on start-up. I can't get it to work cold starting the mini and going into boot mode and choosing the bootcamp bootdisk. The modified EFI does start up, and recognizes the RX5700, but Windows still starts with the Intel 630 from the mac-mini (even though I have that disabled in Win10), and the RX5700 doesn't show up in device manager.
It does work when I boot into Big Sur, connect the Razor, then switch the start-up disk to the bootcamp disk, restart and press Spacebar when the automated EFI shows up.