USB4 Specification Merges Thunderbolt 3 and USB With Transfer Speeds up to 40Gb/s
The USB4 specification for a new version of USB was today published by the USB Implementers Forum [PDF] giving us details on what to expect from the next-generation USB architecture following a preview back in March.
USB4 is a major update that "complements and builds upon" the current USB 3.2 2x2 (USB-C) and USB 2.0 architectures. According to the USB-IF, the USB4 architecture is based on Thunderbolt, doubling the maximum bandwidth of USB and allowing for multiple simultaneous data and display protocols.

The USB-IF outlined key specifications of the USB4 architecture, such as 40Gb/s speeds (twice the current 20Gb/s maximum) and backwards compatibility with USB 3.2 and Thunderbolt 3.
- Two-lane operation using existing USB Type-C cables and up to 40Gbps operation over 40Gbps certified cables
- Multiple data and display protocols that efficiently share the maximum aggregate bandwidth
- Backward compatibility with USB 3.2, USB 2.0 and Thunderbolt 3
USB4 will use the same USB-C connector design as USB 3, which means manufacturers will not need to introduce new USB4 ports into their devices.
Apple's newest Macs offer support for USB-C and Thunderbolt 3, which means most Mac users are already experiencing USB4 speeds when using Thunderbolt 3 cables and devices, but USB4 will make Thunderbolt-style speeds the new default and it will lower the cost of devices that use these faster transfer speeds.
USB Power Delivery will be required in devices built for USB4, which also means we can expect to see higher-powered chargers with multiple USB4 ports.
Though the USB4 specification is complete, it will still be some time before we can expect to see devices that take advantage of USB4. It typically takes at least a year for new products to come out following the finalization of a new specification, so it will be late 2020 or beyond before we begin seeing USB4 devices.
Popular Stories
In his Power On newsletter today, Bloomberg's Mark Gurman said Apple will have a three-day stretch of product announcements from Monday, March 2 through Wednesday, March 4. In total, he expects Apple to introduce "at least five products."
Subscribe to the MacRumors YouTube channel for more videos.
A week ago, Apple invited selected journalists and content creators to an "Apple Experience" in...
Apple is expected to launch a new foldable iPhone this year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that Apple will release its first foldable device in 2026.
Subscribe to the MacRumors YouTube channel for more videos.
Below, we've collated an updated set of key details that have been leaked about ...
Apple's software engineers are testing iOS 26.3.1, according to the MacRumors visitor logs, which have been a reliable indicator of upcoming iOS versions.
iOS 26.3.1 should be a minor update that fixes bugs and/or security vulnerabilities, and it will likely be released within the next two weeks.
Last month, Apple released iOS 26.2.1 with bug fixes and support for the second-generation...
The special new color that Apple is considering for the iPhone 18 Pro and iPhone 18 Pro Max this year is red, according to Bloomberg's Mark Gurman.
Specifically, he said that Apple is testing a "deep red" finish for the two devices.
If this rumor materializes, it would be the first time that the Pro and Pro Max models ever come in red, and the iPhone 18 Pro models would be the first...
Apple has been developing a more affordable version of the MacBook, and it's rumored to be launching in under two weeks. This is going to be one of Apple's most unique Macs, because there hasn't really been anything quite like it before.
We've rounded up everything we know about the low-cost MacBook ahead of its March debut.
Design
Rumors about the MacBook's design make it sound a lot...