[So any one else having good luck with disabling ULPS and PowerPlay? Especially D700 users?
I've been overclocking my D500 nMP this way without any issues since early March. See:
https://forums.macrumors.com/threads/1853090/
I thought someone would like to know that my nMP has not yet exploded ;-)
My maximum overclock with the Omega drivers is 1000 core / 1500 memory. Stability does seem to depend on the game, though. I reverted to the Omega drivers after I found that I was getting quite a few BSODs overclocking with the 15.4 Beta drivers and that they lowered performance in everything but GTA V.
I can report, however, that my method for installing the 15.4 beta drivers HAS WORKED for the strange unofficial version of the 15.5 beta which has been posted by Asder on Guru3d. As others have found, though, that particular version still does not have support for Crossfire in the Witcher 3. I am hopeful that when the "real" 15.5 beta which AMD have promised to us (due to be released soon, apparently) is released, we will be able to use the same method to install those, and that we will then have crossfire support in the Witcher 3.
Incidentally, although I was able to install the 15.5 driver, Catalyst Control Centre was then crashing (something which I've solved before by uninstalling and reinstalling it) and I then tried going all the way back to the "official" bootcamp drivers. It may be my imagination but I think they're a bit better for the Witcher 3 than the Omega drivers, although they can't sustain as high an overclock, it seems.