
The official eGPU support from Apple is coming soon, but it's already available with dev-kit and unofficial eGPU enclosures (they are basically the same ). It should run with any PC having a Thunderbolt 3 port. Not all setups are working correctly yet, but the one I'm using seems pretty stable.
My setup is:
* Macbook Pro (15-inch, 2017) with Radeon Pro 560
* Akitio Node eGPU enclosure (firmware 23.1)
* NVIDIA GeForce 1080 Ti
Resuts:
On macOS HighSierra TouchDesigner placed on external screen accelerated by eGPU is working correctly and is stable. I see about 700% performance increase over the laptop's GPU. When I move the TD window to my laptop's screen, the rendering switches to laptop's Radeon and the window content goes red, I can't do anything about it. I think it's related to Radeon's OpenGL drivers. Probably will be fixed on official Apple release.
On Windows (installed via Bootcamp) TouchDesigner works stable both on internal and external screen.
Other card I've tested on this machine and eGPU is Radeon RX580. On macOS I'm getting red screen both on external and internal display.
Overall I'm happy with the setup. It may be more reasonable to get a desktop PC or a gaming laptop, but if you already own a good laptop that only lacks a descent GPU or you want a Mac with a strong GPU - it could be a nice solution.