USB Implementers Forum announces USB 4, which offers a maximum speed of 40 Gbps, double that of USB 3.2, and support for Thunderbolt 3
Double the speed of USB 3.2 up to 40 Gbps — Hot on the heels of USB 3.2 receiving a confusing Gen 2x2 suffix, the USB Implementers Forum (USB-IF) …
Context & Ripple Effects
USB 4 is the USB-IF's answer to the mess it created with the USB 3.2 specification, whose Gen 2x2 suffix left buyers guessing what a port actually delivered. By folding Thunderbolt 3 into the base spec and doubling throughput to 40 Gbps, the forum is collapsing two competing high-speed ecosystems into one.
The move also sets up the roadmap that followed: Intel later detailed Thunderbolt 4 as fully USB4-compatible, and the Promoter Group's USB4 version 2.0 pushed the same architecture to 80 Gbps.
First-order effects
- Device makers can now ship a single 40 Gbps port that carries both USB and Thunderbolt 3 traffic, removing the need to license and badge Intel's protocol separately on mainstream hardware.
- Buyers get another naming layer to parse on top of the Gen 2x2 confusion, since 'USB 4' ports will vary in real-world capability depending on implementation.
Second-order effects
- Intel loses Thunderbolt exclusivity as a differentiator: once the protocol lives inside the open USB spec, laptop vendors can advertise Thunderbolt-class speeds without an Intel-branded port, pressuring Intel to keep adding value on top — which it did with Thunderbolt 4's multi-monitor guarantees.
- Cable and accessory makers face a new certification tier, since passive USB-C cables rated for 20 Gbps won't carry 40 Gbps, splitting the accessory market by bandwidth.
Third-order effects
- The absorption of Thunderbolt into USB points to one converged wired-interconnect standard rather than parallel ecosystems — a path confirmed when Intel previewed its next-gen Thunderbolt built directly on USB4 v2.
- If each generation keeps doubling over existing connectors, the durable constraint shifts from silicon to cabling, making certified-cable quality the recurring consumer pain point the USB-IF has to manage.
The trend: USB and Thunderbolt are consolidating into a single specification whose speed doubles every few years, with Intel shifting from gatekeeper of the fast lane to contributor to the shared standard.