As of early yesterday, Nvidia rolled out beta Pascal drivers for GPUs on Mac computers. Supported cards include the shiny new Titan XP as well as the GTX 1080. Mac users can grab the drivers directly from Nvidia's website.
This release marks the end of Mac users' reliance on older hardware. Without support for Pascal-based cards, users gaming on Mac had to stick with Nvidia's 9-series of cards built on Maxwell architecture.
Enthusiast games aren't the only ones who will benefit from Pascal support. Plenty of older computers, including hacked "Hackintosh" systems, can take advantage of modern Nvidia GPUs as well.