Apple is supporting external GPUs with High Sierra // US$599 Apple Dev Kit  

Improvements yes. With the GM + HL23T's macOS TB3 firmware & RX VEGA 64 , I was able launch Hitman Metal API benchmark and it went through almost to the end. The app crashed immediately in my previous test. I don’t know if it’s due to firmware or GM build. Probably the latter.

Quite a lot of games already support Metal:

https://en.wikipedia.org/wiki/Metal_(API)

Posted by: FricoRico

Posted by: mac_editor

Posted by: goalque

 

Your problem is very likely the VBIOS. My Sapphire reference RX 480 8GB  + Mid 2015 MBP M370X works via direct TB2 and TB2-to-TB3 adapter on High Sierra (first beta), and DP-DP connection.

This might probably be the case for my GPU as well, albeit an MSI Armor RX 480 4GB. @FricoRico's suggestion might actually work. I believe this is a single 8-pin card, however the VRAM is different.

I can confirm that flashing my XFX RX480 XXX OC Edition with AMD's reference RX480 bios works perfectly. I have acceleration under MacOS and Windows 10 using the Akitio Thunder 2. Do make sure you use a bios with the same VRAM manufacturer, for me it was Samsung.

@FricoRico

How do you flashed you graphic card ? There is a link or video ?

Tks !