nvidia and mac is not the best combo. https://www.amazon.com/GIGABYTE-Gaming-Graphic-Card-GV-RX580... is only 500, almost the same video card, an RX 580.

For Windows, the 1070 / 1080 boxes are better deals, sure, but 1080 box is not 500 but 700. https://www.newegg.com/Product/Product.aspx?Item=N82E1681493..., even the 1070 is more than 500 https://www.newegg.com/Product/Product.aspx?Item=N82E1681412...