I had the same issue others were having from back in January/February and it still does not appear to be solved for my card.
I can fix the 150mhz memory clock by uninstalling Trixx, doing a clean driver uninstall and reinstalling 17.5.2, however any attempt to get my overclock back with Trixx reverts the settings to 150mhz after a reboot.
I thought this issue was solved months ago. Is there another workaround that I missed? I tried to read any and all forum threads related to the issue. Any help is appreciated.