I would make sure you do a clean install of the latest driver again. Use DDU from safe mode. Then run the clean install for the new drivers. If you still have a problem, repeat this function but reload the most recent working drivers. If that then works you have a reproducible issue. I would then report back here as well as filing an issue report with AMD : http://www.amd.com/report
I would also report this to your cards maker as they may be able to qet a quicker ear at AMD.