USB Standard
USB4
USB4 uses USB-C to combine high-speed data and display traffic over a shared link, with the original generation supporting up to 40 Gbps.
Overview · Compatibility · Articles
Related: USB Standards · USB 3.2 · USB4 Version 2.0
USB4 overview
The original USB4 generation introduced 20 Gbps and 40 Gbps operation over USB-C and a tunneling architecture that can share link bandwidth between multiple data and display protocols.
| Connector | USB Type-C |
|---|---|
| Original USB4 data rates | 20 Gbps and 40 Gbps |
| Later USB4 performance | USB4 Version 2.0 extends the family to 80 Gbps operation |
| Architecture | Supports multiple data and display protocols over a shared high-speed link |
| USB 3.2 compatibility | Supported; see USB 3.2 |
| USB 2.0 compatibility | Supported; see USB 2.0 |
| Thunderbolt relationship | Based in part on the Thunderbolt protocol specification contributed by Intel |
| Current status | Original USB4 generation; USB4 continues under Version 2.0 |
Sources: USB-IF USB4 overview, USB-IF USB4 Specification v2.0, and USB-IF USB Type-C Cable and Connector Specification.
USB4 compatibility
USB4 works with USB 3.2, USB 2.0, and compatible Thunderbolt 3 hardware, with speed and features limited by the least capable part of the connection.
| Connection | What happens | Main limit |
|---|---|---|
| USB4 40 Gbps host + USB4 40 Gbps device + suitable cable | Can operate at up to 40 Gbps under the original USB4 generation | All parts of the path must support 40 Gbps USB4 |
| USB4 40 Gbps device + USB4 20 Gbps host or cable | Falls back to up to 20 Gbps | The 20 Gbps component in the path |
| USB4 host + USB 3.2 device | Uses the best mutually supported USB 3.2 capability | The USB 3.2 device, cable, or intermediate hardware |
| USB4 host + USB 2.0 device | Uses the backward-compatible USB 2.0 path | Up to 480 Mbps for High-Speed USB 2.0 data |
| USB4 + Thunderbolt 3 equipment | Can interoperate when the connected USB4 and Thunderbolt 3 implementations support that compatibility | Thunderbolt 3 compatibility support on the specific products |
| USB-C port or cable without USB4 support | The connector may still carry another supported USB mode, but the connection is not USB4 | USB-C describes the connector, not the protocol or speed |
| Hub, dock, or adapter in the path | The link operates at the best capability supported end to end | The slowest or least capable host, hub, dock, adapter, cable, or device |
Sources: USB-IF USB4 overview, USB-IF USB4 Thunderbolt 3 compatibility compliance specification, USB-IF USB4 interoperability test procedures, and USB-IF USB Type-C Cable and Connector Specification.
USB4 articles
Browse guides about USB4 performance, USB-C hardware, cables, compatibility, Thunderbolt interoperability, and practical high-speed connection questions.
