Boot screens, Boot picker screen, works with firmware updates and has Audio out in Mojave and Catalina.
You'll soon be able to put the same card in your 2008-2012 Mac Pro that comes in the new $6,000.00 monster from Cupertino.
Stay tuned for Vega news.
Caveat #1: 3,1 will boot, it is up to you to patch SSE4 libraries, etc. The EFI works, rest up to you.
UPDATE: To clarify, these cards are 95% done. Will be offering 580s for pre-order as soon as I remember how to add a product to the website. US MVC will be shipping within 2 weeks, barring any roadblocks .I believe our European partners will be onboard as well.
With the announcement and Beta of Catalina, it's time to accept reality. Apple and Nvidia seem bound to have effectively ended new Nvidia card support in 10.13.6.
This is sad for a number of reasons, Apple being bad guys is never nice. Guess they got tired of being embarrassed by higher benchmark scores and general love for Nvidia. In any case, unless there is a Blizzard in Hell, it appears that CUDA on Mac ends there too.
There could be a surprise yet, but as of right now, June of 2019, there is no path forward .