http://plugable.com/products/usb3-hub7bc/"USB over-current protection supporting up to 900mA per port (up to 1.5A for BC 1.2 devices)"
It's possible that the hub is shutting down the power at some point. Unless you are planning on running at 300mhz, i would drop the vcore way down.
Trying 175Mhz at 1.25A 4.89 V. Kept getting zombie sticks yesterrday running at 1.5A. I'm running 3 GekkoScience 2Pac on Port 1, 3, and 5.