I have noticed that my XFX Radeon 7770 Ghz edition is running at a GPU clock off 300Mhz, and a memory clock off 150Mhz. In the cayalyst studio in AMD Overdrive; it says my default is at a GPU clock of 1000Mhz and a memory clock off 1125Mhz. I have installed the latest drivers and that still hasn't made a difference.
http://imageshack.us/photo/my-images/707/amdoverdrive.png/
http://imageshack.us/photo/my-images/707/amdoverdrive.png/