what is the difference between usb 1 2 and 3?
When comparing 2.0 and 3.0 there are a few major differences. First the transfer rates: USB 2.0 offers transfer rates of 480 Mbps and USB 3.0 offers transfer rates of 4.8 Gbps - that's 10 times faster. Note that the transfer speeds also depend on the device in use in addition to the bus type and USB ports and cables.