The power does data with 3.0 speed through but only 500 mAh of power per port. USB 3.0 devices, particularly hard drives consume up to 900 mAh and a real USB 3.0 port also provides 900 mAh.
The details of amps per hour I take the back of the package - 500 mAh / port.
In other words, a USB "3" USB device "2" power.