Updated: Mar 7, 2022
In 2008, the Superspeed (SS) USB was announced, the 3rd major adaptation in the USB standard. Initially named USB 3.0, it was later revised twice after inferring successor standards to USB 3.1 Gen 1 and finally to USB 3.2 Gen 1.
After the advent of 3.0 technology, the transmission speed was significantly raised to 5 Gbit/s (625 MB/s), which was relatively faster than the previous 2.0 version with a data transmission speed of 480 Mbit/s. One of the significant improvements in the superspeed USB was up-gradation to full-duplex (can send and receive data simultaneously) communication from half-duplex.
Moreover, USB 3.0 comes with dual bus architecture that facilitates backward compatibility with USB 2.0. One can connect a USB 3.0 peripheral to a host's USB 2.0 port and vice versa. One can even connect a USB 3.0 device to a USB 3.0 port on their computer using a USB 2.0 cable. However, the superspeed transfer rate can only be achieved when the device, the cable, and the port all are USB 3.0.
As technology advances, new kinds of devices, media formats, and enormous economic storage are converging. They need significantly more bandwidth to maintain the interactive experience. To address the need, the USB Implementers Forum (USB IF) announced the 4th major version of the USB standard USB 4.0 (actually named USB4) in 2019.
USB4, which is based on the Thunderbolt™ protocol specification contributed by the Intel Corporation, is a new generation for peripheral connections with the highest bandwidth available in the market today. It provides backward compatibility with USB 3.x, USB 2.0, and even Thunderbolt 3. It doubles the bandwidth of the USB standard when compared to the previous latest USB version. USB4 supports two separate lanes of data which is divided into 20 Gbit/s each. Now we can combine that into a total of 40 Gbit/s, but the advantage of having two separate lanes is that we can have two types of data sent simultaneously to separate signals. So, if we wanted to combine them and send data over both, we get that 40Gbit/s,. Let’s take another scenario where we want to have data sent over one and use the other to display a video, in which case we can have both types of data simultaneously communicated, one display and one just regular data. This is all thanks to using the two separate physical sets of pins and wires on the USB4.
As type C technology has evolved as external display ports for many host products, the USB4 specification uses this underlying protocol. It provides the host the ability to scale allocations for display data flow optimally. Furthermore, since it uses a type C port, it also provides significantly improved power delivery of up to 100 Watts which uses intelligent power delivery and is bi-directional. That means, USB4 cable can optimize power usage, and the power can flow in and out between the coupled device.
USB 4.0 (USB4) is a significant upgrade since the USB 3.0 version, and the compatibility of this turbo USB to previous version USBs (and even the thunderbolt) makes it a new future standard. However, the complete switchover to USB4 may still take time. Moreover, once used widely, the peripheral connection standards will be hassle-free and effortless.