Reboot your machine. I get this on my HDTV once I change my clocks from the default. If it still persists, then somehow the clock speed is "locked" with your driver settings. I don't know where this setting is, but found fully uninstalling and reinstalling the driver and using driver sweeper in between will get rid of the "bad" clock speeds.
Btw this happens to me on a radeon 5870
Thank you.
I forgot to update this thread, but I already solved this problem. It is a 7970 thing I believe. I just had to do /xcl in the properties of the shortcut and reboot my system. Currently doing 1135MHz on stock clocks, won't be downclocking memory because this is mostly a gaming rig