2014 Mac Mini [4th,2C,U] + GTX 1070 Ti @ 16Gbps-TB2>TB3 (ASUS XG Station Pro) + macOS 10.13.6 & Win10 [omardesu]  

System specs

• 2014 Mac mini
• Core i5-4278U, Dual Core @ 2.6GHz, Turbo Boost to 3.1GHz
• 16GB LPDDR3 SDRAM
• 1TB SATA HDD

eGPU hardware

• ASUS XG Station Pro
• EVGA GTX 1070 Ti Gamers (blower)
• Apple Thunderbolt 2 cable 0.5m
• Apple Thunderbolt 3 to Thunderbolt 2 adapter

Installation steps - OS X 10.13.6
(This was a few days ago, and I'm going off of memory.  I'll probably do a clean install again ensure accuracy).

1. Shutdown
2. Hold Cmd+R 
3. Utilities -> Terminal -> csrutil disable
4. Reboot
5. Install and run purge-wrangler (choose option 2: NVIDIA eGPUs and also install web drivers)
6. Install CUDA drivers from Nvidia
7. Reboot and good you should be to go.

I can keep my eGPU plugged in through reboots into 10.13.6 (even in 10.14.3) and the system recognizes it.

Installation steps - OS X 10.14.3
(You can get the eGPU and GPU to show up, but it doesn't work sadly)

1. It's the same as above for 10.13.6 except for step 6 as there are no CUDA drivers for Mojave.

Some of my observations:

• The eGPU will be recognized and the 1070 Ti will be recognized; however, there is NO EGPU FUNCTIONALITY FOR MOJAVE w/nVIDIA CARDS.
• It's funny that iStat Menus actually show it saying it's using the nVidia card, but it actually isn't.
• Also, when I plug the HDMI cable into the eGPU, it just ends up being a black screen; however, the display is recognized but without any video output (will attach some screenshots when I go boot back into Mojave).

Installation steps - Windows 10 (bootcamp) build 1803
(this is an excerpt from OliverB's build as it's the only way it works for me.  Thanks OliverB, your insight has been helpful the last few days)

1) Boot without eGPU Plugged in (It's actually not possible boot with it plugged)
2) Press ALT for the Bootloader
3) Select Windows and wait for the dots appear cycling "plug-ready"
4 When the first reach the upper part of the cycle, plug in the eGPU (This is the only difficult thing here, this is a matter of timing).
5) After Windwos is loaded check for "Display Adapter"s under "Device Manager", if there is a Microsoft Basic Device Adapter (Error 31).
6) If it is not there or something else went wrong (BlueScreen, Didn't Boot at all, etc..) Repeat from 1)
7) Install latest nVidia Driver
8) Hot plug n play the eGPU as you wish.

It works very well, but when you reboot/start the system you have always to hotplug the eGPU at the beginning (Step 4). Once the system is running, you can hotplug and hot-unplug again and again. This solution is best, if you work mostly with Windows. Ok can let it running.

Benchmarks

MacOS Heaven and Valley (OpenGL)

Win10 Heaven and Valley (OpenGL)

Win10 Heaven. and Valley (DirectX11, for comparison with OpenGL)

Win10 AIDA64 GPGPU

Comments

• Not too bad of setup.  The hotplug for Win10 at boot is kind of a bummer, but I can live with it.
• Also couldn't get ASUS AURA RGB software working.  Every time I start the SW, it just says "non-AURA" and won't let me get into the application.
• Fortnite has been much more playable and has a slight edge over the Gigabyte Gaming Box RX580 which I will be returning soon (it's a nice unit which is fully compatible in Mojave with a nice form factor, but I like the expandability of the XG Station Pro and if I really need to be on Mojave, I could always swap in an AMD card).