Posted in driver thread but post here too:
Twice after starting my PC I've had to reapply the overclock on my 9070. Has anyone experienced similar?
If your overclock is stable you can apply it to separate game profiles. In the overclocking tab you have an option for “Add Game Profile” at the top right of the performance/tuning tab. Load (import) your saved profile and the click that add game option.
You can verify what profile is being applied by going to the Gaming tab, selecting your chosen games and hitting the “Tune Game Performance” option.
This way your OC profile will apply even if it has not loaded on startup. AMD have this set as a safety override I think.