10.12 and CCC2
I use a Sapphire Radeon HD4870x2, and I have used it for about a year and a some odd months (since a short time after it was released.) The only time it ran odd- slightly unstable was when using catalyst drivers near launch. THe driver disc included with Sapphire cards usually...
Drivers for HD4870x2
I use the HD4870x2 from Sapphire.
I have had no problems installing or using the Catalyst releases as others here stated.
THe main thing is even if it works there is a strong possibility that any drivers after 10.5 our HD4870x2 are only using 1GPU when running 3d...