Despite looking the same, A USB-C port or cable can support a wide range of speeds, power capabilities and other features depending on the configuration used. For instance, USB 2.0 supports speeds of up to 480 Mbps while the likes of USB4, Thunderbolt 3 and Thunderbolt can handle speeds of up to 40 Gbps.
To make things more interesting, the USB Implementers Forum(USB-IF) has announced the USB4 Version 2.0 spec, which adds optional support for 80 Gbps bidirectional bandwidth as well as the ability to send or receive data at up to 120 Gbps.
When USB-IF first made the USB4 Version 2.0 public in September, they explained it would support a data transfer rate of up to 80 Gbps in either direction. The USB4 Version 2.0 has 4 lanes total, each lane capable of handling 40 Gbps.
By utilizing three lanes to send information one way, and the remaining lane being used to send feedback the other way, USB4 Version 2.0 can hit 120 Gbps.
“Optionally for certain applications, such as driving very high-performance USB4-based displays, the USB Type-C signal interface can be configured asymmetrically to deliver up to 120Gbps in one direction, while retaining 40Gbps in the other direction,” explains USB-IF.
For normal operations, a USB4 version 2.0 port that can handle 120 Gbps operations will still transmit and receive data at 80 Gbps, until it determines that the 120 Gbps/40 Gbps configuration is suitable for the task at hand.
“The USB4 discovery process managed by system software will determine if the preferred mode of operation is the 120Gbps configuration. After initially connecting at 80Gbps, the port will then transition into 120Gbps operation,” explained Brad Saunders, USB-IF board chair and CEO
Bad Saunders explains such a scenario might arise when sending data from a computer to a high-performance monitor at 120 Gbps, with one 40 Gbps lane left available for sending data to the system.
USB4 Version 2.0 is likely to be embraced by very heavy users with extreme display needs that go beyond 4K resolutions with very high refresh rates, while also leveraging other things such as HDR and multiple monitors. Despite the announcement being made this week, the very first products supporting USB4 Version 2.0 should come out in late 2023 or early 2024.
