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.

usbccable
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

iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching in Three Months With These 12 New Features

Saturday June 21, 2025 2:45 pm PDT by
The iPhone 17 Pro and iPhone 17 Pro Max are around three months away, and there are plenty of rumors about the devices from credible sources. Below, we recap key changes rumored for the iPhone 17 Pro models as of June 2025:Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone X...
iPhone 16 Battery Life Feature

iOS 26's New Battery Life Mode Available Only on These iPhone Models

Saturday June 21, 2025 9:02 am PDT by
Last week, we reported that iOS 26 introduces an opt-in Adaptive Power Mode on the iPhone, alongside the existing Low Power Mode. Apple says that Adaptive Power Mode can make "small performance adjustments" when necessary to extend an iPhone's battery life, including slightly lowering the display brightness or allowing some activities to "take a little longer." The full description of...
All Screen iPhone 2027 Feature 1

iPhone Reportedly Moving to All-Screen Design in Two Stages

Sunday June 22, 2025 3:58 pm PDT by
Apple has long been working towards an iPhone with an all-screen design, and it might finally achieve the feat in a few more years from now. In his Power On newsletter today, Bloomberg's Mark Gurman said that Apple will shrink the size of the Dynamic Island on new iPhone models released next year. A year after that, he expects Apple to release a redesigned 20th-anniversary iPhone model....
ios 26 control center b2

Everything New in iOS 26 Beta 2

Monday June 23, 2025 2:57 pm PDT by
Apple provided developers with the second beta of iOS 26, introducing the first changes and refinements to the new operating system since it debuted after the WWDC keynote. Because we're early in the beta testing process, there are quite a few tweaks to iOS 26, which we've rounded up below. Subscribe to the MacRumors YouTube channel for more videos. Control Center The background behind the...
ios 26 control center b2

iOS 26 Beta 2 Fixes Control Center Design

Monday June 23, 2025 10:58 am PDT by
With the second beta of iOS 26 that Apple provided to developers today, Apple addressed one of the major complaints that people have had with Liquid Glass. iOS 26 beta 1 on left, iOS 26 beta 2 on right The Control Center buttons are now slightly more opaque, making it easier to see the different control options even on a multicolored background. The new, more opaque look is apparent with the ...
iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro's Alleged Vapor Chamber Cooling System Partly Revealed

Sunday June 22, 2025 6:37 am PDT by
Apple's upcoming iPhone 17 Pro and iPhone 17 Pro Max models are rumored to be equipped with a vapor chamber cooling system, and a leaker known as Majin Bu today shared a photo of an alleged copper thermal plate for the system. Many high-end Android smartphones like Samsung's Galaxy S25 Ultra are equipped with a vapor chamber cooling system, which can manage heat dissipation inside the...
Wi Fi WiFi General Feature

iOS 26 Adding Two New Wi-Fi Features, Allows AirDrop and AirPlay Alternatives

Saturday June 21, 2025 7:02 am PDT by
iOS 26 is gaining two new Wi-Fi features, including Captive Assist and Wi-Fi Aware. MacRumors contributor Aaron Perris discovered a reference to Captive Assist within the code for the first iOS 26 developer beta, but Apple has yet to enable the feature. It should be available by the time the software update is released later this year. In his Power On newsletter last month, Bloomberg's...
airpods 4 blue

Apple Offering Free AirPods — Here's How to Get Them

Tuesday June 17, 2025 6:33 am PDT by
Apple is running a new promotion that offers free AirPods to qualifying customers. Now through September 30, college and university students in the U.S., Canada, Mexico, and Singapore can receive free AirPods 4 when they purchase an eligible new Mac or iPad from Apple. AirPods Pro 2 are also available at a discount. If you do not want AirPods, the promotion also offers various other...
iOS 26 on Three iPhones

iOS 26 Includes These Five Smaller Features You Might Have Missed

Saturday June 21, 2025 11:18 am PDT by
While the dust is beginning to settle on the first iOS 26 beta, we continue to take a closer look at new features coming with the update. Below, we recap five smaller changes that you might have missed. Emoji Game Apple News+ subscribers in the U.S. and Canada can play a new Emoji Game, which tasks players with completing words and phrases with emoji. This is the fifth game that is...

Top Rated Comments

zedsdead Avatar
76 months ago
One cable to rule them all.

Now lets get USB-C on an iPhone.
Score: 49 Votes (Like | Disagree)
oneMadRssn Avatar
76 months ago
One cable to rule them all.

Now lets get USB-C on an iPhone.
Don't get me wrong, I like USB-C, but it is not the panacea everyone makes it out to be. There is not "one cable." There are a large number of different USB-C cables, all with different specs, speeds, etc.

Inexpensive USB-C charging cables are limited to USB2 speeds and most of them are limited to 30W of power. There are 60W and higher cables, but in 6ft lengths there are not as many options and it's far from easy to figure out what you're going to get. Some suppliers write the limits in terms of watts, some in terms of volts and amps. Most laymen have trouble figuring it all out.

And then there are the chargers... 18W, 30W, 60W, 90W, 100W, 5V, 12V, 18V, 2A, 3A. Chargers with two ports get even more confusing. While it's relatively easy math, I don't think having people doing Ohm's Law calculations in their heads when buying chargers in cables is user-friendly.

But I mentioned basic charging cables are super slow for data. If you want to use a USB-C cable for data, then it's even more confusing. Speeds vary depending on cable length and spec variant compatibility - a USB-C Gen 1 vs USB-C Gen 2 vs Thunderbolt 3; 1.5ft vs 3ft vs 6ft. Each combination will have a different max speed. It's all very difficult for most folks to keep straight.

Basically, USB is still a spaghetti of specs and limits, and this is just adding yet another layer. Just because the physical plug of Type C is nice, does not mean all the other USB problems are solved.
Score: 33 Votes (Like | Disagree)
Internet Enzyme Avatar
76 months ago
Congratulations Apple, you were four or five years early—you certainly earn that distinction. Too bad that the products in the meantime were entirely unflexible and annoying for anyone who wanted to conveniently use their laptop as a computer
Score: 16 Votes (Like | Disagree)
Spock Avatar
76 months ago
I don’t even have a Mac with USBC yet..
Score: 12 Votes (Like | Disagree)
tofagerl Avatar
76 months ago
Will USB4 then drop support for USB-A, B and B's little cousins mini and micro? Because if so, it's about time!
Score: 10 Votes (Like | Disagree)
zakarhino Avatar
76 months ago
Lightning is still the most robust port design I've ever come across for serious charging/data capabilities. I can plug my phone in every day multiple times a day for two years and the port will still be solid enough to dangle the iPhone from its charging cable no problem. Meanwhile the USB C ports on my MacBook are stupidly loose after just a couple months of use to the point where occasionally the charger would unplug itself if you move the laptop in a strange way.

I know this is controversial but I'd much rather keep a robust port on the iPhone (lightning) than a convenient yet fragile one (USB C).
Score: 7 Votes (Like | Disagree)