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USB 3.0 Promises Faster Speeds, Backward Compatibility

By Melissa J. Perenson
January 6, 2009 12:00 PM ET

PC World - Nearly a decade after USB 2.0 was first introduced, this practically ubiquitous technology is poised for its first major upgrade in years. Symwave, a semiconductor start-up, and hard-drive maker Seagate are showing the first working demonstration of SuperSpeed -- otherwise known as USB 3.0 -- at CES 2009. The company's demo setup includes an adaptation of an external Seagate FreeAgent hard drive equipped with the new interface, and shows the high read/write throughput and streaming video performance potential of USB 3.0.

Solid operating-system drivers and mature chip sets helped USB 2.0 evolve into a formidable and dominant interconnection technology for attaching devices to your system. However, in our increasingly high-definition world -- a world where many households as well as businesses are verging on the use of terabytes of data, not just gigabytes -- the case for greater bandwidth is clear.

Enter USB 3.0, which promises faster speeds and backward compatibility with the 10 billion USB devices shipped to date.

Early in 2008, Symwave began work on a USB 3.0 physical-layer device, the new cable that will be able to transport the format's higher bandwidth, in anticipation of the spec being completed by late last year. When the spec went to its first public 1.0 release at the SuperSpeed USB Developers Conference last November, Symwave was the only company ready with a proof-of-concept product.

Faster Throughput

According to Symwave, the new cable dramatically improves throughput speed -- even now, in its early development stages. Where USB 2.0 offers speeds of 480 megabits per second, USB 3.0 jumps to a theoretical 5 gigabits per second. "In our simulations, we're seeing in the neighborhood of six to seven times the throughput, at least 150 megabytes per second [equivalent to 1.2 gigabits]. The theoretical improvement is 10 times," says Craig Stein, vice president of engineering. "We think that, over time, as more software optimization is done, we'll get closer to the theoretical improvement. We think somewhere near 250-300 megabytes per second [or up to 2.4 gigabits per second] is where USB 3.0 will top out when it matures."

Stein says the company's target is to enable peripheral devices with USB 3.0 to roll out in time for the 2009 Christmas shopping season. Even if PC adoption of USB 3.0 lags, he adds, "we think there's opportunity for consumers to future-proof the products they buy."

According to the spec, USB 2.0 cables and devices will be backward-compatible with the new USB 3.0 port. The cable, the host device (for example, the PC), and the peripheral device all must be USB 3.0 capable to achieve the 3.0 speeds; otherwise, the connector drops down to the lowest common denominator, USB 2.0 speeds.

Reprinted with permission from PCWorld.com. Story copyright 2012 PC World Communications. All rights reserved.
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