@rednow what miner are you using for the Nvidia cards? I was using ethminer and it kept resetting the hbcc every so often. What scheduled tasks were there to disable? Would love to get more cards up in this rig. Also do you use afterburner to tune the Nvidia cards?
I'm using different ccminer versions as well as EWBF Zec miner. Scheduled tasks - there were 2 nvidia tasks scheduled to run once a day. After disabling it - speed is constant high now.