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USB3.0 standard launched into market in 2008. Transmission rate is up to ten times as USB2.0 whose speed is 480Mbps. USB3.0 is up to 4.8Gbps. Although many devices doesn't require so high rate, hard disk, card reader and other devices require high speed. Compared with USB2.0, USB3.0 is more energy conservation. Besides , USB3.0 is compatible downwards and supports USB2.0 devices.