USB4, In 2019, USB-IF integrated the Thunderbolt 3 protocol (TBT3) on the basis of USB 3.2 , launched USB4 Gen 2x2 and USB4 Gen 3x2. The difference between the past is that the name USB 3.2 is still retained. USB4 is a doubling of the original USB 3.2 transmission speed, reaching 40Gbps, which is the speed of USB4 Gen 3x2. USB4 supports both USB 3.2 and TBT3 transfers. In short, USB4=USB 3.2+TBT3. USB4, like USB 3.2, also has single channel mode and dual channel mode. The USB4 interface and USB 3.2 interface both support the use of the USB PD fast charging protocol.

USB4 integrates multiple protocols as well as support more devices simultaneously, which involves bandwidth allocation. As shown in the figure below, USB4 can allocate up to 22Gbps of bandwidth for data transmission and at least 18GB of bandwidth for display support. Can connect a display with a resolution of 5120x2880 (5k), a refresh rate of 60Hz, and a color depth of 30bit, leaving 18Gbps of bandwidth for data transmission; You can also connect two videos with a resolution of 4096x2160 (4k), a refresh rate of 60Hz, and a color depth of 30bit, leaving 8Gbps of bandwidth for data transmission.

USB， is abbreviation of"Universal Serial BUS". It is an external bus standard to standardize the connectiondu of computer and peripheral equipment and communications. Is the application interface in the PC fieldtechnology。 USB interface， Plug and Play and hot swap support equipment functions， USB is the end of 1994by Intel， Compaq， IBM， Microsoft and other companies jointly proposed.

The fourth Generation： USB 3.1(USB 3.1 Gen2) maximum transfer rate of 10Gbps， downward compatible with USB1.1/2.0/3.0

USB， is abbreviation of"Universal Serial BUS". It is an external bus standard to standardize the connectiondu of computer and peripheral equipment and communications. Is the application interface in the PC fieldtechnology。 USB interface， Plug and Play and hot swap support equipment functions， USB is the end of 1994by Intel， Compaq， IBM， Microsoft and other companies jointly proposed.

The Third Generation： USB 3.1(USB 3.1 Gen2) maximum transfer rate of 10Gbps， downward compatible with USB1.1/2.0/3.0

USB， is abbreviation of"Universal Serial BUS". It is an external bus standard to standardize the connectiondu of computer and peripheral equipment and communications. Is the application interface in the PC fieldtechnology。 USB interface， Plug and Play and hot swap support equipment functions， USB is the end of 1994by Intel， Compaq， IBM， Microsoft and other companies jointly proposed.

The second generation： USB 2.0 transfer rate up to the maximum 480Mbps USB 1.0/1.1 and USB 2.0 interface is compatible