I'm running 3 hubs. I can run 8 on 2 hubs or 9 on 3 hubs but as soon as I add one more stick the problems start.
Check this out -
https://forums.raspberrypi.com/viewtopic.php?f=28&t=53832I finally figured it out. I'm running 16 sticks now @500Mhz on 2 hubs. Probably can even run on single hub, but will need voltmeter and pod adjusting...
My problem was that both of my 30 port hubs are constructed with 8 usb hub chips each. Each chip controls 4 ports, so its like 8 separate 4 port hubs connected.
For my two hubs system actually sees 16(!) 4 port hubs. It just cant support that many hubs.
Each hub has 2 usb cables, one for each side, so each usb cable supports 15 ports or half the hub. I originally had all 4 cables plugged in into the PI.
What I did - I only connected 2 cables to the pi, each cable goes to a half of each hub and loaded them with sticks (with single port spacing)
This achieved voltage/amperage needed to run the sticks (both sides share the power line) without overloading the system with amount of hubs connected.
I can only run 16 sticks this way, it will do for now.
Hope this makes sense.
I was able to remove a hub that my keyboard and mouse were using, so now I can run 10 sticks. Starts doing the same thing again when I try to go to 11 now.