I have a Sapphire Radeon hd6850 toxic, when I went into MSI Afterburner it didn't even recognize a shader clock. I tried GPU-Z and it didn't either. Why?
ATI's shader clock is linked to the core clock and is, as far as I know, uneditable. ATI uses Stream Processors (SP's) and nVidia dubbed their Shaders 'Cuda Cores' (which run at twice the core speed).