Update: Some of the information in this article is out of date, please refer to our guides for current information! - Guide to USB 3.0 and USB-C Guide!
Intel recently announced some of the key features and benefits of the new USB 3.0 "SuperSpeed" specification, which will be released in conjunction with it's new Extensible Host Controller Interface (xHCI). How does this new standard differ from USB 2.0? Let's take a look:
For starters, the maximum data transfer rate of the USB 3.0 standard has increased to 4.8Gbps, ten times the capability of the 2.0 version. USB 2.0 is capable of 480Mbps, while USB 1.1 can only run at 12Mbps. This added speed will come in handy as we see more and more adoption of HD technology, which means much larger sizes for digital video files.
The added speed capability of revision 3.0 is made possible through the addition of five new data lanes; one pair for sending data, one pair for receiving data, and one additional ground. This means that the new standard is capable of true Bi-Directional data transfer with simultaneous sending/receiving, which will allow for faster reading & writing to digital storage devices and faster 'syncing' with PDA's. These new data lanes are fiber-optic, which accounts for the dramatic increase in transfer rate. However, the four copper conductors used by USB 2.0 and 1.1 are retained in the connector. The added lines make for a thicker cable, roughly the thickness of a CAT-5E Ethernet cable.
The new standard is 100% backwards-compatible with the USB 2.0 and 1.1 revisions. This is possible due to the design of the USB 3.0 connector. The five new fiber-optic pins are situated on a different plane than the copper conductors used by the older USB standards. That means that you can use a USB 3.0 cable in a USB 2.0 port, and vice-versa. The only exception to this is the Mini-B connector, which has been completely redesigned. The 3.0 and 2.0 cables are easily distinguishable from one another with a quick glance at the connectors.
Another benefit of the 3.0 standard is an increase in it's power capabilities. The new interface carries a power output of 900 milli-amps, increased from USB 2.0's 100 milli-amps. This allows several devices to be powered from the same USB 3.0 hub, and also allows one to charge USB-powered devices (such as cellphones, MP3 players, cameras, and PDA's) much faster.
USB 3.0 saves power, too. By implementing a new interrupt-driven protocol for powering USB devices, it saves power that would normally be used in 'device polling', or sending constant signals to search for data traffic on the bus. Instead of being constantly drained of power by the 'searching' controller, devices will instead send a signal to the controller to begin data transfer. In this way, they remain in a true 'standby' or 'sleep' mode when not sending or receiving data, and will not waste power unnecessarily. This feature will also work with USB 2.0 devices that are plugged into a USB 3.0 controller. This is great news for laptop owners seeking longer battery life.
So when will you see USB 3.0 controllers and devices on the market? It is estimated that USB 3.0 controllers will be available for purchase by consumers by mid-2009, with the first devices that support the new standard being released in 2010. It is possible that hardware manufacturers may push for an early release of devices to make the 2009 holiday season.
