When I turned my computer into a Hackintosh about 2 years ago I was using an NVIDIA GTX 660 as my GPU and it worked without any additional drivers because of built-in support in Sierra. When I later bought a 4K display I could not make the GTX 660 drive the display at 4K@60Hz in macOS, although it worked well in Windows.
NVIDIA web drivers
I decided I needed a more powerful GPU anyway to play games on the new display in Windows so I bought a GTX 1060. It worked in Sierra and High Sierra thanks to the so called web drivers; GPU drivers provided my NVIDIA on their website. Without the web drivers you get no hardware acceleration, no 4K as maximum resolution, just one display working … the whole setup is basically unusable.
Those web drivers are version specific, every time the macOS build number changes after some update you need new ones (or to use a script to patch the previous ones). This is a bit annoying, you typically have to wait a few days after every macOS update for new drivers to become available and update then.
No web drivers for Mojave
When a new major version of macOS comes out, like Mojave, you cannot use web drivers for the previous version. NVIDIA needs to release new drivers and they now cannot do it without cooperation from Apple. Citing from the NVIDIA Developer forums
Developers using Macs with NVIDIA graphics cards are reporting that after upgrading from 10.13 to 10.14 (Mojave) they are experiencing rendering regressions and slow performance. Apple fully controls drivers for Mac OS. Unfortunately, NVIDIA currently cannot release a driver unless it is approved by Apple.
Apple basically blocks NVIDIA from releasing web drivers for Mojave, that is the reason the drivers are not out even now half, a year after Mojave release. If you are for example an iOS developer, XCode 10.2, the next version of Xcode, will only run on Mojave and you will not be able to use it unless you upgrade.
AMD GPUs in Mojave
Mojave natively supports some GPUs from AMD. You can buy a RX 560, RX 570, RX 580, Vega 56 or Vega 64 and it should work out of the box, no extra drivers needed. You not even have to install Lilu or Whatevergreen.[Read More]