Speed
Currently, there are 3 speed modes defined by the latest USB 3.0 specification. They are Super-Speed, Hi-Speed and Full-
Speed. The new SuperSpeed mode has a transfer rate of 4.8Gbps. While the specification retains Hi-Speed, and Full-Speed USB
mode, commonly known as USB 2.0 and 1.1 respectively, the slower modes still operate at 480Mbps and 12Mbps respectively
and are kept to maintain backward compatibility.
USB 3.0 achieves the much higher performance by the technical changes below:
• An additional physical bus that is added in parallel with the existing USB 2.0 bus (refer to the picture below).
• USB 2.0 previously had four wires (power, ground, and a pair for differential data); USB 3.0 adds four more for two pairs of
differential signals (receive and transmit) for a combined total of eight connections in the connectors and cabling.
• USB 3.0 utilizes the bidirectional data interface, rather than USB 2.0's half-duplex arrangement. This gives a 10-fold increase
in theoretical bandwidth.
With today's ever increasing demands placed on data transfers with high-definition video content, terabyte storage devices,
high megapixel count digital cameras etc., USB 2.0 may not be fast enough. Furthermore, no USB 2.0 connection could ever
come close to the 480Mbps theoretical maximum throughput, making data transfer at around 320Mbps (40MB/s) — the actual
real-world maximum. Similarly, USB 3.0 connections will never achieve 4.8Gbps. We will likely see a real-world maximum rate
of 400MB/s with overheads. At this speed, USB 3.0 is a 10x improvement over USB 2.0.
Applications
USB 3.0 opens up the laneways and provides more headroom for devices to deliver a better overall experience. Where USB
video was barely tolerable previously (both from a maximum resolution, latency, and video compression perspective), it's easy
to imagine that with 5-10 times the bandwidth available, USB video solutions should work that much better. Single-link DVI
requires almost 2Gbps throughput. Where 480Mbps was limiting, 5Gbps is more than promising. With its promised 4.8Gbps
speed, the standard will find its way into some products that previously weren't USB territory, like external RAID storage
systems.
Listed below are some of the available SuperSpeed USB 3.0 products:
• External Desktop USB 3.0 Hard Drives
• Portable USB 3.0 Hard Drives
• USB 3.0 Drive Docks & Adapters
• USB 3.0 Flash Drives & Readers
Technology and components
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