What processor are you interested in using?
We dropped support for Windows 8 in our Catalyst 14.6 Beta driver. I would recommend upgrading to Windows 8.1, it's free.
Microsoft seems to not want people to use Win 8 and instead encourages people to use Win 8.1. Below is the Windows min requirement link which requires a min 1 GHz. processor speed. Thus virtually any recent AMD processors would work but depending on your needs some models may work better than others.