The combination of this box and a compatible AMD GPU (RX 470, 480, 570, or 5800 will be much cheaper, though less powerful, than Blackmagic's solution. You'll need to supply your own AMD graphics card for the box, but the box connects via Thunderbolt 3 for maximum throughput. If you want a less expensive eGPU solution for your Mac, try Sonnet's eGFX breakaway box.
