USB4
USB · 4 specs
Direct Answer
USB4, released August 2019, is built on Intel's Thunderbolt 3 protocol, donated to USB-IF as the new foundation -- up to 40 Gbit/s, a mandatory USB-C connector, and tunneling that lets a single port carry USB, DisplayPort, and PCIe traffic at once. Thunderbolt 3 compatibility is required; Thunderbolt 4 compatibility is optional for device makers.
Source: USB-IF · Last reviewed Aug 28, 2026
Specs
| Released | August 2019 |
| Max Bandwidth / Data Rate | Up to 40 (Gen 3x2) or 20 (Gen 3x1) Gbit/s |
| Connector Required | USB-C only |
| Protocol Foundation | Intel Thunderbolt 3 (donated to USB-IF) |
A New Foundation, Not Another SuperSpeed Increment
Unlike every prior USB generation, which extended the original USB architecture with faster signaling, USB4 (released August 2019) is built directly on Intel's Thunderbolt 3 protocol, which Intel donated to USB-IF as royalty-free. That gives USB4 a genuinely different core capability: protocol tunneling, letting a single physical USB-C port and cable carry USB data, DisplayPort video, and PCI Express traffic simultaneously, dynamically dividing bandwidth between them as needed.
USB4 requires host and device support for Thunderbolt 3 compatibility, but full Thunderbolt 4 compatibility -- which adds stricter minimum requirements like guaranteed 40 Gbit/s and mandatory PCIe/DisplayPort support -- remains optional for manufacturers, meaning not every USB4 device offers the exact same guaranteed feature set.