I made sure to roll back my drivers to 12.3 cause i heard they may not support 12.4 by release. Plus 12.4 suck anyways. Where in that article does it say 7850 will be supported. Im only seeing 7870 and 6850.
Even though it doesn't outright mention it, your 7850 will run it. It's built on the same architecture as the 7870.