USB 3.0, also known as SuperSpeed USB, is the next major revision of the Universal Serial Bus (USB), a hardware interface that supports the exchange of data between a host computer and peripherals. Enhancements in the USB 3.0 specification were driven by the need for faster transfer rates and better power efficiency.
USB 3.0 vs. USB 2.0
SuperSpeed USB is ten times faster than USB 2.0 (also called HighSpeed USB) and increases the power output from about 100 milliamps to 900 milliamps.
Unlike USB 2.0, which could only handle traffic in one direction, USB 3.0 has a dual-bus architecture. This allows the bus to read and write at the same time, significantly speeding up the time it takes to transfer data to and from a peripheral device.
USB 3.0 also replaces device polling with an interrupt-driven protocol so that idle devices don't have their power drained by the host controller as it looks for active data traffic.
All USB 3.0 connections and cables are backwards compatible with USB 2.0 ports, although USB 3.0 cables are slightly thicker than USB 2.0 cables.
The Universal Serial Bus Revision 3.0 Specification provides the technical details to understand USB 3.0 requirements and design USB 3.0 compatible products.