OKAY.  Tried a fresh reformat and it didn't work.  However, I then rolled back the kernel to 4.4 and uninstalled, then re-installed the AMD drivers.  This seems to have solved it.

Doing this, I was able to get the card running at 23.4MH/s which is acceptable.  I have 4 cards on risers now running all at 23-24MH/s.  Tomorrow, I'll try adding a 5th and then 6th card and see if I can get a reliable 6x570 setup on this new chipset.  Thanks for all the replies guys!