Finding the fastest USB connection used to be easy: choose USB 3.0 instead of 2.0. But now, you’ll need to know the difference between USB 3.2 Gen 1, Gen 2, and Gen 2×2—and what various types of “SuperSpeed” mean, too.
USB Naming Used to Be Simple
Once upon a time, USB came in two main flavors, 2.0 and 3.0. All you needed to know about them was 3.0 was faster than 2.0. You could buy a USB 2.0 flash drive and plug it into a computer that had USB 3.0 slots, and it would still work—just at the slower USB 2.0 speeds. Buying a USB 3.0 drive and plugging it into a USB 2.0 port would give you USB 2.0 speeds, too.
If you wanted the fastest speed possible, you’d get a USB 3.0 drive and plug it into a USB 3.0 USB port. It was simple and straightforward. But everything changed with USB 3.1.
USB 3.1 Muddied the Naming Waters
The USB Implementors Forums (USB-IF) maintains USB specifications and compliance, and it’s behind the naming schemes found on USB cables and devices. When it introduced USB 3.1, rather than keep things simple and let that name differentiate from USB 3.0, it called the new standard “USB 3.1 Gen 2.” USB 3.0 was retroactively renamed “USB 3.1 Gen 1.”
To further complicate things, the transfer speeds themselves received names. USB 3.1 Gen 1, originally known as USB 3.0, is capable of 5 Gbps transfer speeds—that’s called SuperSpeed.
USB 3.1 Gen 2 is capable of 10 Gbps transfer speeds—that’s called SuperSpeed+. Technically, it accomplishes this by using 128b/132b encoding in a full-duplex communications mode. Full-duplex communication is exciting because that means information can be transferred and received at the same time. That’s why it’s faster.
The difference between the two was slightly confusing. But, as long as you remembered Gen 2 was better than Gen 1, you were good to go. To help differentiate the speeds, USB-IF also implemented logos, which manufacturer can only use by passing a certification to prove a cable matches the promised specs.
USB 3.2 is Even Faster and More Confusing
Last September, the USB-IF detailed out new possible speeds for USB-C, and the beginnings of the USB 3.2 specification. USB 3.2 will be capable of 20 Gbps speeds. That’s double the transfer speeds of USB 3.1 Gen 2. If you’re wondering how the cables are doubling their speed so quickly without changing size or connectors, it’s straight forward. USB products capable of 20 Gbps have two 10 Gbps channels. Think of it as more wiring jammed into the same cable.
Just like in previous iterations, this new standard is backward compatible for basic usage—but you won’t get the faster speed without all new hardware. If you buy a hard drive that promises a 20 Gbps transfer rate and plug it into your current computer, the hard drive will work, but at slower speeds that the USB ports on your machine can provide. You’ll have to update both ends of the connection to enjoy all the new benefits.
