What do you mean by stuck at lowest clock speeds?
Are you talking about the clock speeds displayed on catalyst control center > overdrive?
Clock speeds displayed on overdrive are the current clock speeds they increase as you put load to it like playing a game.
When you play a game are the speeds also at the lowest?
I'd have to double check what it does when playing a game.. I tried to once before and didn't see any change. My clock speeds on my 6670 changed when I over-clocked it, and my 7950 radeon just displays the same (300MHz GPU clock) and (memory clock: 150MHz) I re-installed windows 7 64bit, and all drivers and all windows updates.. I don't know why its not changing..
Its catalyst 12.11 beta drivers..i have same issue with my gigabyte 7950 stuck at 500 mhz when i try to overclock...read that lots of people having same issues..try diwngrading to older amd drivers or just wait for new ones..