USB-A vs. USB4 2.0

USB-A (Standard-A) is the flat rectangular connector on host ports -- computers, chargers, hubs. It used 4 pins for USB 1.x/2.0 speeds; a 9-pin variant, adding 5 SuperSpeed contacts, extended it to USB 3.0+ in 2008 without changing the external shape or requiring a new socket design.

USB4 2.0, released September 2022, doubles USB4's ceiling to 80 Gbit/s symmetric -- or an asymmetric 120/40 Gbit/s split favoring one direction for high-bandwidth uses like external displays. It requires new cables explicitly rated for the higher speed; existing USB4 v1 cables aren't guaranteed to reach it.