Tried toggling HBCC in global settings, devcon.exe, nothing seems to turn on HBCC. I have 12 GPU rig prepared but this ... HBCC just does not work on 12 GPU drivers.
What version of Windows do you have? The Fall Creators Update (1709) is
supposed to correct those limitations.
I have the Fall Creators Update. According to my understanding, the limitation is caused by drivers, not by Windows. Now, i use blockchain drivers.