USB4 and Thunderbolt 4 are coming to a device-port near you, adding yet another set of options to the confusion of possibilities that is USB-C. 

Key Takeaways

  • USB4.0 is like USB 3.2, only faster. Thunderbolt 4 is exactly the same as Thunderbolt 3.0 in terms of speed and capabilities.You’ll still probably end up grabbing the wrong cable.

The good news is, Thunderbolt 4 is easy. The bad news is that USB4 doesn’t get any less confusing. Either way, all your old USB and Thunderbolt devices will still work when plugged into the new ports. But we’re getting ahead of ourselves. Thunderbolt is still better, but less better. And USB4 is faster but still fragmented and still far too dependent on identical-looking cables. 

“Thunderbolt 4 cables are just about the most universal cable you can get right now. Compatible with all versions of Thunderbolt, as well as any spec of USB-C, including USB 4,” says Thunderbolt accessory maker CalDigit on Twitter.

Rollin’, in My 4.0

The first point of confusion is with the names. USB-C is the name of the port and the plug. USB-3.0, 3.1, 3.2 gen.2, and 4.0 are the names of the various USB standards that use that same port. Thunderbolt also uses this same port and plug. And to add to the confusion, the same port can be used to provide power only, without any data. 

The problem, though, is never the ports, but the cables. A six-foot cable designed for charging phones may or may not pass any data, and if it does, it will be way short of the USB-3.2 spec. And if you want to use Thunderbolt devices, you’ll need to use fancy Thunderbolt-certified cables, which are expensive. Pro tip: look for Thunderbolt devices that include a cable in the box. It’s guaranteed to be compatible and can save up to around $50. It’s not worth cheating out on a Thunderbolt cable.

Also important is length. For a cable to provide full USB 3.2 gen.2, or 4 speeds, it has to be pretty short. Whereas a USB-C power cable only needs to provide power, so it can be much longer. 

In short, USB-C and Thunderbolt are great, as long as you have the correct cable. If not, it quickly turns into a nightmare. 

“Some devices cannot be charged with chargers supporting Power Delivery, even though they have a USB-C port. For example, my OnePlus phone charger will not charge my Google Pixelbook,” electrical engineer Rob Mills told Lifewire via email. “Considering the common physical USB-C interface is the same, there is no way a consumer would be able to figure this out. One solution would be to mark the chargers clearly as supporting a certain power standard.”

4 vs 4

Let’s take a look at the difference between Thunderbolt and USB. They share the exact same port but offer different capabilities. Thunderbolt is a superset of USB. If you have a Thunderbolt port on your computer, you can also plug any USB-C device into it, and it will just work.

Thunderbolt 4 is actually the same as Thunderbolt 3 in every way, except that it adds compliance for USB4, whereas Thunderbolt 3.0 was only guaranteed to work with USB 3.

Historically, the main difference between TB and USB has been speed and bandwidth. Thunderbolt offers up to 40 GB/s data transfer, but now USB4 has caught up, with the ability to offer the same speed. This is fantastic for stuff like USB-C SSD drives or big USB-C displays, but some USB4-compatible computers will only provide 20 GB/s, which is permitted by the 4.0 specs. 

But Thunderbolt still has a few advantages. One is that Thunderbolt is designed to be daisy-chained, so you can plug one Thunderbolt device into, say, a MacBook Pro and then plug another Thunderbolt device into the first one. The second device receives power and can theoretically run at full speed (depending on how much data the first Thunderbolt device is using). 

So, What Can You Do With Them?

The short answer is “anything, only faster.” USB-connected SSDs can now run as fast as Thunderbolt ones. A Thunderbolt 4 dock should be able to offer an array of super-fast USB4 ports, which might end up saturating your Thunderbolt connection, but will be a lot of fun until you do.

In the end, USB4 doesn’t solve the biggest problem of USB-C—the easy-to-mix-up cable types—but it will make everything faster, which is always good news.

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