And again, you are wrong. That list has never changed. It includes only retail Apple supported cards. All the cards on that list are supported natively by MacOS drivers. My GTX 1080 is also not on the list, but it's supported just like your GTX 970 with the Nvidia Web Driver.
Lou
Hi, I am having also problems with my nVidia 980 GTX on my Mac Pro 5.1, it worked fine with El Capitan and when upgraded to High Sierra now it does not work, but it is not exactly the same problem as described here, my Mac recognizes the name of the card, installs the drivers succesfully, but when I restart, before the Apple Logo shows there are some black background console prompts and then loads the system but does not use the nVidia driver and the video is completely slow. Heeeeelp please!