What is USB 3.0 and How is it Different From USB 2.0 and USB 1.1?
USB 3.0 is the next major revision to the Universal Serial Bus (USB) technology standards, and offers the same plug and play capabilities as previous generations (USB 2.0 and USB 1.1), but with a ten-fold performance increase and better power management capabilities. The performance increase is achieved through a technology called SuperSpeed, which allows multiple streams of data transfer while boosting peak bandwidth up to 4.8Gbp/s.
Are USB 3.0 Devices Compatible with USB 2.0 or USB 1.1 Devices?
USB 3.0 devices are downward compatible and can be used with USB 2.0 and USB 1.1 ports, and connectors, but won't be able to take advantage of the SuperSpeed technology when connected in this manner. In order to use the SuperSpeed technology, a USB 3.0 device will require both a USB 3.0 cable and port, as well as a USB 3.0 host controller on the computer.