sunk818, if you look at the chart, it shows that you should only need 1.32V to run at 200mhz. If you have them at 1.5V you are pulling around 1.82A. Can you check the specs on the pluggable hub? The one I saw mentioned a limit of 1.5A/port.
Is this what you have?
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.
I have the USB 2.0 version, but the specs should be the same otherwise except for max data transfer speed.
At 200 Mhz, I'm reading 4.86 V 1.45 A = 7.047 W. My KillAWatt is reading 9.2 W on the wall. I was thinking my settings would be okay because iPad takes 12W to charge and Plugable was handling it okay. I'll try the new setting and see how it goes! I love this community... thank you for your suggestion and help!