The USB Implementers Forum (USB-IF) has formally announced the USB4 version 2.0 specification, after teasing it earlier this year. The new version of the USB specification promises up to 80Gbps of bi-directional data using four lanes. This will be supported on existing 40Gbps USB4 passive cables, along with new 80Gbps specific cables.
In addition to the 80Gbps of bidirectional bandwidth, however, the new specification also has a new special mode where three of the four lanes can pass data in the same direction, meaning you get t120Gbps of data in one direction, with 40Gbps in the opposite direction. This specification is meant for specific use cases, such as extremely high-resolution displays, where it makes sense to have a lot of bandwidth going in a single direction. Support for this capability is optional, however.
Notably, this new version of the USB4 specification also comes with improvements to the data and display protocols. For data, the USB4 link now supports the new Enhanced SuperSpeed USB tunneling, which means you can get bandwidth up to 20Gbps for data alone. That may sound confusing, but a lot of the maximum bandwidth of the USB4 link is typically reserved for display signals or PCIe, so a 40Gbps port wouldn’t necessarily get you higher speeds if you just connected an external drive to it.
Additionally, USB4 version 2.0 also incorporates DisplayPort 2.1, the latest version of this specification that was introduced earlier this week. These updates are meant to align with each other, and they improve efficiency when passing a DisplayPort signal through the USB4 link. The new USB specification also supports PCIe 4.0, which should improve performance for external graphics cards on devices that support them.
Along with the new USB specification itself, there are also new versions of the USB Type-C and USB Power Delivery certifications to align with these new capabilities. As a reminder, USB Power Delivery was recently upgraded to support 240W, so the capabilities of USB-C ports are growing quickly. As usual with USB, a lot of these features are optional, so you’ll have to rely on specific branding for certified products to see what features are supported on that product. The branding should indicate the maximum bandwidth and power delivery speed (if power delivery is supported).
Source: USB-IF
