USB 3.2 was announced about two years ago with speeds of up to 20 Gbps using existing USB 3.1 Gen 2 USB-C cables, but the USB Implementers Forum has done a bit work more and just released the USB4 specification allowing twice the speed at 40 Gbps.
The USB4 architecture leverages the Thunderbolt protocol specification that was recently contributed by Intel Corporation to the USB Promoter Group, enables the faster data rate, as well as multiple simultaneous data and display protocols.
Highlights of USB4 standard
- Two-lane operation using existing USB Type-C cables and up to 40Gbps operation over 40Gbps certified cables
- Multiple data and display protocols that share the maximum aggregate bandwidth
- Backward compatibility with USB 3.2, USB 2.0 and Thunderbolt 3
- Up to 100 Watts power delivery
Both USB 3.2 and USB4 require USB-C cables to make use of the maximum transfer rate, so traditional USB cables may fade away in the future.
It may take a while before we see hardware with USB4, as USB 3.2 was announced in 2017, but we are only now promised high-end desktops and laptops with USB 3.2 port later this year (2019). So if USB4 follows the same schedule, USB4 capable hardware will see the light of day sometimes in 2021.