AMD have announced that their driver has received Microsoft certification. Unfortunately it looks like it won't be appearing until later this summer.
Reference:
AMD Catalyst receives Windows 8 certification | Game Blog
Preview Driver:
Link Removed
amd
apus
catalyst
certification
compatibility
evaluationdriver
firepro
gaming
graphics driver
hardware certification
power consumption
quality assurance
radeon
reliability
sleep resume
stereo 3d
video api
wddm 1.2
windows 8
windows update
