Apple became the first supplier to release the new USB4 connectivity interface when they released their M1 chip MacBooks and MacBook Airs.
So what is USB4?
Very simply, USB4 is the latest generation of USB connectivity.
With increased speed of hardware and ever increasing demands of professional, and even gaming, software, there's a corresponding significantly higher data performance required to maintain peak performance.
USB4 is that major update of USB that hopes to provide that extra hardware and software demand.
Based largely upon Apple's existing Thunderbolt 3 specification, USB4 complements and builds on the existing USB-C, 3.2 and 2.0 architectures. The result is that you can plug a USB-C cable into an USB4 port and it will operate normally as USB-C. The socket remains the same as that which has been used for several recent versions of USB, most popularly known as USB-C.
However, USB4 doubles the maximum bandwidth of USB and, as with Thunderbolt 3, enables multiple simultaneous data and display protocols. USB4 can dynamically share a single high-speed link with multiple end devices, so that the priority task or process is allocated the bulk of bandwidth.
USB Type-C connector has has become an almost default interface for modern computers and devices, so the introduction of USB4 allows for that backward compatibility whilst at the same time allowing users to buy new USB4 hardware without being penalised by different connectors or incompatible protocols.
As per Apple's famous tagline - "it just works".
So there's 100% compatibility with existing USB-C, USB 3.2, USB 2.0, and Thunderbolt 3 devices. USB4 can support 3 speeds: 10Gbps, 20Gbps, and 40Gbps.
The great step forward is that USB4 allows for dual lane operation using existing USB Type-C cables and up to 40 Gbps operation over 40 Gbps certified cables, such as HomeKit Australia's 100w 5A USB4 cable that includes an E-Marker verification chip in its design.
USB4 also supports the USB PD charging standard. Put simply, M1 MacBooks and MacBook Airs, a future iPhone, existing Android smartphones and other devices can charge significantly faster over USB4.
For PC fans, Intel began the integration in 2019 of Thunderbolt 3 into their CPUs as of their tenth generation Core processors.