USB 3.0

USB 3.0 (renamed to USB 3.1 Gen 1 in 2015) is the third major version of the Universal Serial Bus (USB) standard for interfacing computers and electronic devices. Among other improvements, USB 3.0 adds the new transfer mode SuperSpeed (SS) that can transfer data at up to 5 Gbit/s (625 MB/s), which is about ten times faster than the USB 2.0 standard. USB 3.0 connectors are usually distinguished from their USB 2.0 counterparts by blue color-coding of the receptacles and plugs, and the initials SS.

A successor standard, USB 3.1 (renamed to USB 3.1 Gen 2 in 2015), was released in July 2013 with the new transfer mode SuperSpeed+ that can transfer data at up to 10 Gbit/s (1.25 GB/s, twice the rate of USB 3.0), bringing its theoretical maximum speed on par with the first version of the Thunderbolt interface.

Overview

The USB 3.0 specification is similar to USB 2.0 but with many improvements and an alternative implementation. Earlier USB concepts like endpoints and four transfer types (bulk, control, isochronous and interrupt) are preserved but the protocol and electrical interface are different. The specification defines a physically separate channel to carry USB 3.0 traffic. The changes in this specification make improvements in the following areas: