Any USB device will only run as fast as the slowest usb input. you can attatch a usb2 device to usb2 or usb1. If you attach a usb2 device to a usb1 port it it will only run at usb1 speed. When you say Ac powered hub do you mean a powered USB hub? It would be better if you use a powered usb hub, and attatch to usb2 for better speed and reliability.(the powered hub is usually usb2).