'Super Speed' Unleashed with USB 3.0

Computing and consumer devices are increasingly becoming bandwidth intensive
and USB 3.0 is their answer. It allows much faster data transfer and better
power management over USB 2.0. The new version of USB also called SuperSpeed can
achieve a maximum theoritical tranfer speed of 4.8Gbps which is 10 times faster
than the 480Mbps offered by USB 2.0. Practically, it would achieve 3.2 Gbps or
more after including protocol overheads. This kind of speed is just about enough
to transfer a 25GB HD movie in about a minute. Of course, you won't be able to
maximize your bandwidth unless you're using a USB 3.0 cable with superspeed
devices and ports.

Backward compatibility

The new 3.0 connectors and cables will be physically and functionally
compatible with  older spec.  USB 2.0 cables worked off  four lines, USB 3.0
adds five new lines (the cable is noticeably thicker), but the new contacts sit
parallel to the old ones on a different plane. This means you'll be able to
differentiate between 2.0 and 3.0 cables just by looking at the ends.The five
new pins are situated deeper in the connector than the legacy pins, allowing the
deeper new connector to connect the extra pins.Your existing USB 2.0 gear will
work on version 3.0 ports and vice versa. Plugging a 3.0 device into a 2.0 port
or a 2.0 device into 3.0 a port will get you standard USB 2.0 data rates.

Bi-directional

The USB 3.0 protocol is now full-duplex; devices can send and retrieve data
simultaneously, which wasn't true with USB 1.1 and 2.0. That promises to allow
simultaneous downloading and uploading at fast speeds, a potentially tremendous
convenience.This is achieved by adding two new lanes dedicated to transmit data
and another pair for receiving it, bringing the total number of connections from
four on USB 2.0  to nine counting the 3.0 ground contact.

Power optimization

USB 3.0 cables facilitate carrying more power, too. Due to  the growing
number of portable devices that charge via USB, the USB 3.0 has acknowledged the
need for more charging options and have bumped the power output from about
100miliamps to 900 milliamps. That means not only will you be able to power more
devices from a single hub, but the increased current will let you charge up
hefty hardware as well.

USB 3.0 connector pins sit on a different plane allowing backward compability. The USB 2.0 port will be connected by the front legacy pins as always.

More power efficient

One of the mandates of the new spec is more efficient power-usage protocols.
USB 3.0 works on the principle of providing more power when required and wasting
lesser power when not required. USB 3.0 abandons device polling in favor of a
new interrupt-driven protocol, which means non-active or idle devices (which
aren't being charged by the USB port) won't have their power drained by the host
controller as it looks for active data traffic. Instead, the devices will send
the host a signal to begin data transfer. Minimum device operating voltage is
dropped from 4.4 V to 4 V.  New power management features include supports for
idle, sleep and suspend states, as well as link-, device-, and function-level
power management. Devices can communicate new information such as their latency
tolerance to the host, which allows better power performance.

Devices

High-bandwidth devices will  be among the first to migrate to the new
interface. The new interface will allow massive increase in external drive
performance, and drives will once again differentiate themselves on performance.
Solid state devices will benefit most from the speed boost.  External hard
drives capable of more than twice the throughput available from USB 2.0, and
bus-powered portable drives that require non-compliant Y-cables to get the
current they require for reliable operation will also benefit from the power
management option delivered by USB 3.0.

Besides storage, any high-bandwidth device that works with USB 2.0 will work
better if  updated with USB 3.0 support. Some possible applications include
high-resolution webcams, external Blu-ray drives, large LCD monitors capable of
being hooked up via a simple USB connection, digital cameras, video cameras and
more.

With its promised 4.8Gbps USB 3.0 will allow for consumer applications that
were either clumsy or downright unreachable before, like external RAID storage
systems. Photo libraries will transfer many times faster, and syncing video
content between devices will become more convenient.

Comparison with other similar technologies

'FireWire' is a highly efficient peer-to-peer, full-duplex, non-polling data
communications protocol with very low overhead. FireWire's P2P architecture can
achieve much closer to its theoretical 800Mbps data rate than the master/slave
architecture of the USB. FireWire 3200 promises a transfer rate of 3.2Gbps.

FireWire is able to produce about twice as much power as USB. FireWire 3200
is also backwards compatible with FireWire 800. But it should be noted that if
you have a new FireWire 3200 cable/device you can use it with your old FireWire
800 port and still achieve 3.2Gpbs speeds. This feature is a one up on USB 3.0.

Intel talks of a high-speed optical cable interface for PCs called 'Light
Peak' that promised a 10Gb/s transfer rate, or twice the speed of USB 3.0, with
the potential ability to scale to 100Gb/s. Light Peak is being developed as a
way to reduce the proliferation of ports on modern computers and could
eventually replace the plethora of interfaces currently used, from USB itself to
HDMI, DisplayPort,  LAN and so on. But until this comes up, USB 3.0 should be
the technology which takes the cake.