USB4 vs Thunderbolt 3

USB-C wasn't just a long-awaited release of a reversible, high-speed USB connection with advanced Power Delivery and DisplayPort support, it was also the death knell of a variety of different USB connections. It meant the industry could move towards one that was more unified and standardized than ever. USB4 will do that once again, bringing an end to a variety of USB speeds and their various nomenclature. It will also share many of the same specifications as Thunderbolt 3.

That will leave many wondering how the USB4 vs Thunderbolt 3 battle stacks up. Is one faster than the other? Is Thunderbolt 3 still worth looking for in a new device, or is USB4 enough?

USB4 vs Thunderbolt 3 – The differences and similarities

The debate over USB4 vs Thunderbolt 3 isn't a complicated one, as both connectors share many of the same fantastic features. Both have the same maximum data rate of 40Gbps (or around 5 GB/s), and both support charging up to 100W with USB Power Delivery. With charging and data horsepower, both are excellent options for charging everything from smartphones, right up to high-powered gaming laptops.

Both connectors are based on the USB-C standard, too, making them entirely reversible. They're also compatible with existing USB 3.2 devices and support the DisplayPort protocol for handling external displays.

USB4 is also backward compatible with Thunderbolt 3, letting Thunderbolt 3 cables work just fine on a USB4-equipped laptop or similar device. That isn't mandatory though, so it will be up to the laptop or device manufacturer to include that support.

USB4 can come in several different modes ranging from 1 lane 10Gbps to 2 lane 40Gbps. Make sure to consult the devices specifications for this information, as all USB4 ports won't necessarily have the same specs.

USB 4 vs Thunderbolt 3 – which is which?

With a few functional and feature differences between USB4 and Thunderbolt 3, it's important to know which is which when buying a new device that may, and can, support both. Both standards use the USB-C connector, making them look rather similar from a quick glance. That said, Thunderbolt 3 connectors have a small lightning bolt logo next to them to help differentiate them.

While Thunderbolt 3 is always easily distinguishable by the logo, there is a lot more to look for with USB4. As seen below, USB-C ports should (but not always) have a speed rating designated next to the USB logo. For USB4, look for the USB logo with 40 before it.

USB4 vs Thunderbolt 4

USB 4 and Thunderbolt 4 are functionally almost identical. Thunderbolt 4 doesn't upgrade the main features or specifications of Thunderbolt 3, but it does raise the bar for its support. Thunderbolt 4-supported devices must guarantee at least 32Gbps in PCI Express bandwidth to the port. The speed guarantee means all Thunderbolt 4-compatible devices support at least two 4K external displays, or a single 8K display.

That guarantee is one area that Thunderbolt 4 can stand apart. Where it will mandate a high minimum standard for connection speed, USB4 devices can technically still be considered USB4 and support the more traditional USB 3.1 SuperSpeed+ connection of just 10Gbps, or USB 3.2 SuperSpeed++ 20Gbps.

Thunderbolt 4 and USB4 cables will be entirely interchangeable, and will be backward compatible. Thunderbolt 3 cables will also work with Thunderbolt 4 and USB4 connections. Older USB-C 3.2 connections will work with USB4 connections, but won't be able to offer the fastest 40 Gbps transfer speeds.