I have recently built a new rig with 13 P106-100 ASUS cards on nv0019 running -200cc 1550mc and PL90. I have a weird problem that after some time the hashrate on all cards drop by 50% or more and doesn't go back up, the miner doesn't restart and it just keeps running with lower hashrate. This time it did this after 7 hours , with 7 cards running it was up for over 12hours and no problems. Has anyone experienced this before and maybe you know where the problem is?
How is the temperature of your cards? Have you configured nvOC to use auto temp control? If you have, it may be the case that you set the temp too low for what can be reached with 100% fan speed. In this case, auto temp control will smartly reduce the power limit to cool the cards, but of course this reduces the hash rate. Just a guess...