USB 3.0 Is Backward-Compatible, but Theres a Hitch

By Chris Preimesberger  |  Posted 2009-01-02 Print this article Print

USB 3.0 is backward-compatible with all prior USB devices, although there is a hitch: Actual data speeds will always revert to the lowest USB version being used in the system.

For example, for USB 3.0 to work as fast as it is supposed to, all three key components in a network-the host (for example, a PC), the connected device (say, an iPod) and the connecting cable-all need to be USB 3.0-equipped. If any one of those three is USB 2.0 or 1.0, then the component with the oldest protocol dictates the speed of the data transfer.

People have been waiting for faster USB connectivity for a long time; however, it is still going to take a while for the swift new protocol to become embedded as standard within hardware.

"It will probably take five to 10 years for this to become standardized in all PCs, handhelds and connectors," O'Neill said. "But that's reality in the industry. If you follow the development of Ethernet, from 100Mb to 1Gb to 10Gb Ethernet, each one of those steps came within three to five years of each other. They've gone, like, 100X [in speed] in six or seven years."

The USB 1.0 standard was introduced and promoted by Intel in the mid-'90s, with USB 2.0-the most common version now used in PCs, handhelds and storage controllers-coming along in 1998.

USB 1.0, still in use on older computers, offers 1Mb, 6Mb and up to 12Mb per second data transfer speeds. USB 2.0 features 12 Mb/ps and up to 480Mb/ps speeds.

Thanks to leaner protocol code and vastly improved drivers, USB 3.0 is expected to reach speeds up to 5Gb/ps-a tenfold improvement.

Chris Preimesberger Chris Preimesberger was named Editor-in-Chief of Features & Analysis at eWEEK in November 2011. Previously he served eWEEK as Senior Writer, covering a range of IT sectors that include data center systems, cloud computing, storage, virtualization, green IT, e-discovery and IT governance. His blog, Storage Station, is considered a go-to information source. Chris won a national Folio Award for magazine writing in November 2011 for a cover story on and CEO-founder Marc Benioff, and he has served as a judge for the SIIA Codie Awards since 2005. In previous IT journalism, Chris was a founding editor of both IT Manager's Journal and and was managing editor of Software Development magazine. His diverse resume also includes: sportswriter for the Los Angeles Daily News, covering NCAA and NBA basketball, television critic for the Palo Alto Times Tribune, and Sports Information Director at Stanford University. He has served as a correspondent for The Associated Press, covering Stanford and NCAA tournament basketball, since 1983. He has covered a number of major events, including the 1984 Democratic National Convention, a Presidential press conference at the White House in 1993, the Emmy Awards (three times), two Rose Bowls, the Fiesta Bowl, several NCAA men's and women's basketball tournaments, a Formula One Grand Prix auto race, a heavyweight boxing championship bout (Ali vs. Spinks, 1978), and the 1985 Super Bowl. A 1975 graduate of Pepperdine University in Malibu, Calif., Chris has won more than a dozen regional and national awards for his work. He and his wife, Rebecca, have four children and reside in Redwood City, Calif.Follow on Twitter: editingwhiz

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