Everything You Need to Know About USB Ports and Speeds (2024)

The very name Universal Serial Bus (or USB) is an ambitious promise: one port to rule them all. The reality is unfortunately more complicated than that. Even though your phone, tablet, and laptop all use the same USB-C port to charge and transfer data these days, they can all operate differently.

What is USB 4? What is Thunderbolt? Is it the same as USB-C? I’m here to help you answer all these questions, so you can get the most out of your devices.

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USB Glossary of Terms

First, it is important to define a few terms beforehand.

USB 2.X/USB 3.X/USB 4

Every USB device is built to a version of the USB specification, maintained by the USB Implementer’s Forum (USB-IF). These versions are primarily characterized by how much data they can transfer and how much power they can supply (at least, those are the main things you need to consider). While most of these devices are interoperable as long as they use the same port type, the entire chain will conform to the slowest part of the chain. Let’s say you plug a USB 3.2 SSD into a USB 3.2 port on your computer, but you’re using a USB 3.0 cable: data will only transfer at USB 3.0 speeds. Make sure each link in your chain is rated for the speed you need.

USB Power Supply (or USB-PD)

Instead of carrying a charger for every device you own, you can opt for a charging adapter that can charge multiple devices via multiple USB-C Power Delivery (USB-C PD) ports. Power Delivery is a fast charging method that supports up to 240 watts of power and allows gadgets to securely communicate with chargers to determine the appropriate power requirements. You’ll also find these types of ports on USB hubs, sometimes called “passthrough charging,” though that’s not an official term.

Make sure the wattage of a USB-C port on a charging adapter or hub can handle your device’s needs. A MacBook Pro typically requires 96 watts during heavy workloads (though you can always charge them at a lower wattage), so you’ll likely want a 100-watt USB-C port on your charging adapter or USB hub for the best charging experience.

USB-C and USB-A

These terms refer to the physical shape of the connectors and ports on devices. USB-C is common and looks like a small, elongated oval. It’s also reversible, so you can’t plug it in the wrong way. USB-A is the old rectangular port you’ve seen for years. There are many more types of USB connectors, but these are the two you’re most likely to see in charging adapters, hubs, and docking stations today.

Very fast

You may also see some USB devices marketed with terms like “SuperSpeed,” “SuperSpeedPlus,” and “SuperSpeed ​​USB 5/10/20 Gbps.” These terms were originally intended to be more useful and marketable labels to indicate the generation or speed of a USB port, but unfortunately, it only made things more confusing. In most cases, you can ignore these labels and look at the actual speed ratings.

What’s happening with USB generations?

It would be nice to be able to plug a USB 3.2 device into a USB 3.2 port using a USB 3.2 cable and have the device work properly. Unfortunately, it’s much more complicated than that.

When USB 3.0 was released in 2008, its maximum speed was around 5 gigabits per second (Gbps). However, when USB 3.1 was released in 2013 with a maximum speed of 10 Gbps, the 5 Gbps version was renamed USB 3.1 Gen 1, while the newer, faster specification was USB 3.1 Gen 2. Are you still confused? Well, it’s about to get even worse.

After the release of USB 3.2 in 2019, USB 5Gbps was renamed Again Moving from “USB 3.2 Gen 1” to “USB 3.2 Gen 2,” the 10Gbps version became “USB 3.2 Gen 2,” and the new 20Gbps spec became, you guessed it, USB 3.2 Gen 2×2. Wait, what? The “2×2” refers to running two lanes of data simultaneously at 10Gbps. You don’t need to know all that. Many USB hub and dock manufacturers have ditched the names, labels, and symbols. They’ve started printing the maximum speed right next to the ports.