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What is Thunderbolt, and is it different from USB-C?

Thunderbolt is a type of hardware interface technology that is used to connect various devices to a PC. You’ve likely already seen Thunderbolt in the form of its distinctive ports and cables — the latest generations use the USB-C connector. That’s the quick definition. But if you’re here, you’re probably looking for a more comprehensive explanation of what Thunderbolt is, and why it differs from USB-C.

In this guide, that’s exactly what you’ll get: We’ll go over some of its current iterations and how they compare, how Thunderbolt is different from USB-C, how to identify Thunderbolt ports, and find out the latest on when Thunderbolt 5 will launch. Now let’s take a closer look at Thunderbolt.

Thunderbolt 3 vs. Thunderbolt 4

Close up of ports on a 2016 MacBook Pro.
Bill Roberson/Digital Trends

Since Thunderbolt was introduced in 2011, there have been a number of different versions of it. But these days, if you’re shopping for a device that features Thunderbolt’s use, you’re probably looking at Thunderbolt 3 and Thunderbolt 4.

Introduced in 2015, Thunderbolt 3 features a USB-C connector, a max transfer speed of 40GB/s, and up to 15W of power for running accessories. It can also support one 4K display and is compatible with USB4 specification.

Launched in 2020, Thunderbolt 4 is the latest version of its connection technology that’s currently available. Thunderbolt 4 still has the same max transfer speed as Thunderbolt 3: 40Gb/s, but it mandates that as the minimum, whereas for Thunderbolt 3, it’s not enforced. Like Thunderbolt 3, Thunderbolt 4 also has a USB-C connector and offers up to 15W power delivery for accessories. But that’s where the similarities between the two pretty much end.

Unlike Thunderbolt 3, Thunderbolt 4 can support two 4K displays and is rated as “compliant” for USB4 specification. Thunderbolt 4 also has double the PCIe SSD bandwidth speed (32 Gb/s) of Thunderbolt 3 (16 Gb/s).

Is Thunderbolt the same as USB-C?

Rear view of an iMac sitting on a white table next to a potted plant. A view in which you can see the iMac's selection of ports.
Dan Baker/Digital Trends

No. Though Thunderbolt has recently incorporated the use of USB-C connectors, they’re still different connection technologies. So just because Thunderbolt 3 and 4 ports are designed for use with USB-C connectors, not all USB-C ports are designed to support Thunderbolt.

Do Thunderbolt and Thunderbolt 2 accessories work with Thunderbolt 3?

Close up of white Thunderbolt cables on a white background.
Image used with permission by copyright holder

They can, but not without help. Thunderbolt 3’s USB-C connection isn’t compatible with devices based on Thunderbolt or Thunderbolt 2 without an expensive adapter.

How do I know if I have a Thunderbolt port?

There are two main ways to know: You can either see if there is a thunderbolt icon next to your device’s USB-C port or you can check your device’s tech specs online to see if it mentions Thunderbolt ports in the product description.

When will Thunderbolt 5 launch?

While Intel officially introduced Thunderbolt 5 in September 2023, the exact launch date for Thunderbolt 5 has not been announced yet. Thunderbolt 5-based products are currently expected to begin their release at some point in 2024.

We’ll update this section once we know more.

Anita George
Anita has been a technology reporter since 2013 and currently writes for the Computing section at Digital Trends. She began…
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