The new spec, predictably called the USB4 Version 2.0, brings support for up to 80GBPS bi-directional bandwidth, made possible by up to four transfer lanes. This infrastructure will even make it possible to transfer data at up to 120GBPS in one direction through three lanes while maintaining 40GBPS in the other direction.
This new spec takes advantage of a new physical layer architecture based on PAM-3 signal encoding, which doubles the potential speeds of Thunderbolt 4 USB-C cables, which currently can only go up to 40GBPS. What speeds you actually get will be determined by the system software, which will check what kind of data configuration your system can support.
This will make it possible to connect high-spec devices through USB C cables, such as monitors with resolutions beyond 4K, or ones that support extremely high refresh rates, HDR output and other modern features. You can even string a bunch of monitors together for a high-speed multi-monitor gaming setup.
Other potential applications include the use of this protocol for high-speed data transfer in external SSDs and GPUs that are currently hindered by the potential bottlenecks of modern USB-C hardware. You can even support USB 3.2 tunnelling at up to 20Gbps, which is twice the speed of previous gen versions.
While these are certainly upgrades worth getting excited about, you will still have to wait quite sometime before you get to enjoy them since USB4 Version 2.0 cables and adapters will not hit the open market for another 12 to 18 months.