This could be a power problem, the ports on that hub are only rated at 2 amps each. What frequencies are you running at? Some miners have been known to draw to much power when they go bad. Pull the bad ones and one more and try and run 8 in every other port on that hub.
I could be wrong, but I had the impression that all the ports are fed directly from the powersupply and not individually through a usb hub chip. The total rated power is 40A which should be plenty, but I can see from the significant voltage drop that isn't optimal. I am not sure how the core voltage depends on the supply voltage and if it matters.
If you dont want to invest in a higher powered usb hub.
Well, the Eyeboot 19 port 40A is more or less mil-grade, made of sturdy metal, looks very nice, but as jstephanop wrote a while ago, he wasn't sooo enthusiastic having noticed problems with the pins and the power capability. This monster cost me a fortune because alternative hubs from Amazon didn't ship to my country. It is almost embarrassing to note how much I paid for the think when I finally had it (with shipping and taxes).
For each miner undervolt all memory voltage to as low as you can before they stop hashing.
Yes I did all that, also core. I feel I have a good control in general. What I learned is that stability is way more important than a slightly higher hashrate. Nothing is as frustrating as that the MLDs have stopped hashing, or for some reason drop out. One MLD no problem, all 11, impossible, lately the 'best' 8 - also impossible. I am sure it is this hub. That's why it can't be stressed enough that if you're running more than 1-2 MLDs that you really really pay attention to what hub you are getting.
if your running 11 miners check the warmth of your psu.
Nah, never really warm. maybe 100W, no problem. I would say not more than maybe 25degs (in room temp <15degs C).
Thanks for all the feedback!