I have a R9 280X and a Radeon HD 7950 in crossfire.
When I manually set the clocks in Radeon Settings I can't change them back to default.
So I increase the memory clock for my 7950 from the default 1250MHz to 1350MHz (I'm increasing a little on the 7950 and decreasing on the R9 so that they are the same).
Once I set it to 1350MHz, I cannot get it back to it's default 1250MHz (even clicking the reset button). 1350MHz becomes the lowest option available, whereas usually it should be 150MHz.
It has done this on all the crimson editions (up to and including 16.1.1.
I've just resorted to OC Guru II to set the clocks for me.