I know that in Mountain Lion, Apple added drivers for Radeon HD 7000-series graphics cards and in March 2013, Sapphire released the Mac 7950. I've seen people use Dual 5770s and 5870s in their Mac Pros and I'm wondering if you can do the same thing with 2 Sapphire 7950s or 1 Sapphire 7950 and 1 PC 7950 (the benefit Mac + PC cards would be seeing the Apple logo on startup and having the benefits of 2 graphics cards, while also spending less money on a PC 7950)