The fastest RX580 available for the Mac Pro with a boot screen

MSI RX 580 ARMOR 8G OC


System requirements:
- Apple Mac Pro 4,1 or Mac Pro 5,1
- installed macOS High Sierra or newer
- native support by macOS High Sierra, Mojave,

For Catalina, Big Sur, Monterey or higher such as Sequoia
(any version of OSX above Mojave requires you to use Opencore Legacy Patcher
as later versions of OSX are not officially supported but work)

Key features:
- compatible with macOS and Windows (via BootCamp)
- supports Apple boot screen (gray screen with Apple logo on startup) on all ports (also on 4K displays)
- supports PCI Express 2.0 link under macOS and Windows

- supports three displays simultaneously:
2x hdmi ports
2x display port
1x dvi port
You may require display adapters to suit your configuration, if unsure please ask

- supports 4K/60Hz via DisplayPort via HDMI Port
- supports OpenGL, OpenCL and Metal in applications and games
- allows an upgrade to macOS Mojave or macOS Catalina
- supports sound via HDMI under macOS

Comes with video card and power cable

I also have other parts for the power mac 5.1 or even a complete Mac Pro 5.1, look at my other advertisements