USB 3.0 Is Backward-Compatible, but Theres a Hitch
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."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.
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.