I'm having a hard time getting consistent USB 3.0 speeds from my external USB 3.0 drives and RAID. Most of the time, the ports get configured to "Hi-Speed USB (2) for reasons I can't understand. If I reboot several times, it will eventually connect at the correct speed. According to Apple USB 3.0 FAQ, "The first device you plug in will configure the port, so always connect USB 3 capable hubs or devices first." I have three USB 3.0 drives connected directly to the 2012 iMac, along with a USB 3.0 hub connecting a few USB 2 devices. When I boot up, I check the System Information and usually see one USB 3.0 bus and 3 USB 2 buses, even though the attached devices should be detected as USB 3.0. How could the buses be configured incorrectly if the only device connected to them is USB 3.0? Do each of the 4 USB port correspond to one of the buses? By default, I see that two of the ports are automatically assigned to the Facetime HD camera and Bluetooth host controller, respectively. Is this interfering the the configuration of the ports? If a combination of USB 3.0 and 2 devices are connected to the same USB 3.0 hub, how will the port be configured? I'm baffled.