USB4 eats Thunderbolt 3 for the 40 Gbps super-cable in 2021

USB4 eats Thunderbolt 3 for the 40 Gbps super-cable in 2021

Lindsey Duncan
March 5, 2019

With the announcement of the USB4 (no space!) specification, the group has reached the apex of powerful features/confusing nomenclature. Now, we are looking further into the future, with USB-IF announcing the initial spec for USB 4.

In an effort to make Thunderbolt ubiquitous, Intel is sharing its TB protocol with the USB Promoter Group.

When will the first consumer devices with USB4 support be released?

Thunderbolt 3 has been one of the (optional) crown jewels of USB Type-C, providing a blistering 40 Gbps theoretical bandwidth compared to USB 3.1 Gen 2's 10 Gbps.

The standard is set to support 40Gbps speeds and the Thunderbolt 3.0 standard - following Intel opening the licencing of the technology to manufacturers.

Device makers will be able to make Thunderbolt devices without paying royalties to Intel, which should make adoption easy.

Hot on the heels of releasing the USB 3.2 specification - and the abject confusion it's likely to cause consumers - the USB Implementers Forum (USB-IF) announced that the 40 Gigabits per second (Gbps) data transfer rates and multiple 4K display support that are exclusive to Intel's latest proprietary Thunderbolt 3 port will be made available to generic USB-C ports. This do-it-all connector can link virtually any peripheral-even ones that are daisy-chained together-at astonishing speeds of up to 40Gbps, all while delivering enough power to charge batteries, too. Introducing USB4 is sort of like hitting the reset button on USB. From the USB 3.2 specification document: "One bus is a USB 2.0 bus (see Universal Serial Bus Specification, Revision 2.0) and the other is an Enhanced SuperSpeed bus (see Section 3.1)".

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There have also been several connectivity standards within and alongside USB 3.2, for example.

Because any new USB 3.x subsumes the earlier USB 3.x specifications, the USB-IF prefers to categorize not by number (eg, USB 3.2, USB 3.1, and so on) but by speed. There is just one connector (Type-C), it supports Thunderbolt, and there is just one version rather than Gen 1, Gen 2, and Gen 2x2.

The primary goal of USB is to deliver the best user experience combining data, display and power delivery over a user-friendly and robust cable and connector solution.

The USB-C connector was created to be future proof and reversible.

Essentially, then, the emergence of USB 3.2 and USB4 mark a huge push away from USB Type-A ports towards USB Type-C ports. That means we can expect two-lane operation with data transfer speeds of up to 40 Gbps, which is twice what USB 3.2 boasts.

That has ramifications for the way companies built their products. It is not uncommon, especially for low-end devices, to only support USB 2.0, or include more USB 2.0 ports than USB 3.0 ports. It's likely that will continue for years to come, but perhaps with an increasing percentage of USB Type-C to USB Type-A.