●USB1.0 appeared in 1996 with a speed of only 1.5Mb/s (bits per second), and in 1998, USB1.1 was upgraded to a speed of 12Mb/s.

●The USB2.0 specification is an evolution of the USB1.1 specification. Its transmission rate reached 480Mbps, which is 60MB/s when converted to MB;

● The latest USB 3.0 has a maximum transmission bandwidth of up to 5.0Gbps, which is 640MB/s.

USB3.0 introduces full-duplex data transfer. Of the 5 lines, 2 are used to send data, the other 2 are used to receive data, and 1 is ground. In other words, USB 3.0 can simultaneously read and write at full speed.

● 3.0 compatible with 2.0, vice versa, the essential difference is the read and write speed, the former is faster than the latter, and much faster, the former voltage is greater than the latter;

●In terms of appearance, USB2.0 usually uses a black or white interface, while USB3.0 uses a blue interface.

● USB 3.0 transfer rate up to 10 times that of USB 2.0, USB 2.0 has a rate of 480 Mbps, while USB 3.0 can reach 4.8 Gbps. Of course, many devices don't need such high speeds, but devices such as hard drives and card readers still require a lot of speed. USB 3.0 will be more energy efficient compared to USB 2.0. In addition, USB 3.0 is backwards compatible, supporting USB 2.0 devices.
From the point of view of the USB socket pins, USB2.0 uses a 4-pin design, while USB3.0 adopts a 9-pin design, which is more powerful in comparison.
●What is the difference between USB3.0 and 2.0 from the appearance of the USB male port, the USB3.0 interface part is marked with the "SS" style, while USB2.0 is only marked with the ordinary USB general logo.
USB 3.0 features interfaces that are compatible with legacy standards, support for universal I/O, and will be optimized to reduce power consumption while improving protocol efficiency in the computer, consumer, and mobile markets, support for fast synchronous mobility, support for both optical and digital component specifications, and the ease of use and plug-and-play features of traditional USB technology. Mini USB 3.0 has interfaces will be divided into A, B two kinds of male ports (Plug), and the female port (Receptacle) will have B and AB two, from the shape point of view, AB female port can be compatible with A and B two kinds of male ports, at the same time, you can see that the 3.0 version of the male port is 9 pins, and 2.0 is 5 pins. For backward compatibility with version 2.0, USB 3.0 features a 9-pin design, four of which have the same shape and definition as USB 2.0, while the other five are specifically prepared for USB 3.0.