What's The Difference Between USB 3.1 Gen 1 And USB 3.1 Gen 2?

As you breeze through spec tables of new products, you’ll often find a mess of “USB” references. USB has become ubiquitous on devices from smartphones to massive gaming systems and all manner of miscellaneous consumer electronic devices, but a few years ago, we started seeing more types of USB emerge, which clouded and cluttered the connectivity world a bit. Specifically, people seem to get tripped up by the differences between USB 3.0, USB 3.1 Gen 1, and USB 3.1 Gen 2. Fortunately, it’s pretty simple to understand once you dig into the topic.

Forget About USB 3.0

First of all, USB 3.0 doesn’t really exist anymore. The USB Implementers Forum (USB-IF) chose to absorb the USB 3.0 spec into the USB 3.1 Gen 1 spec. Because of that, "The terms USB 3.0 and USB 3.1 Gen 1 are synonymous," a USB-IF representative told Tom's Hardware years ago when we first wrote about this issue. It’s essentially a clerical decision, as the USB-IF explained: "By incorporating USB 3.0, we're reducing the number of documents a developer needs to reference (we're talking hundreds and hundreds of pages of technical documents that developers have to parse through) and including all relevant information to ensure products are properly developed to be backwards compatible (protocol-wise, not related to cables/connectors)."

Therefore, if you see “USB 3.0” on a product, it’s probably a few years old. On anything made recently, you’ll see only “USB 3.1” or “USB 3.1 Gen 1” in its place. (There is one caveat to know, which we’ll discuss in a moment.)

Gen 1 Vs. Gen 2, And A Branding Issue

The difference between USB 3.1 Gen 1 and USB Gen 2 is as simple as this: Gen 1 offers 5Gbps speeds, whereas Gen 2 offers 10Gbps. Seriously, that’s it.

The USB-IF never intended for the those terms to be used in marketing materials, though. To help clarify the two different speeds of USB 3.1 and the various other protocols that can run over USB connectors (eg, Type-A and Type-C), the group created terminology and visual branding. For example, USB 3.1 Gen 1 is “SuperSpeed USB,” and USB 3.1 Gen 2 is “SuperSpeed USB+.” From there, the logos that OEMS were supposed to slap onto their products were designed to indicate if a port was capable of, for example, Power Delivery or DisplayPort.

We charted all of this out in this longer explainer, but it’s almost moot at this point. The industry never really picked up on the nomenclature and branding, so everyone just calls them “USB 3.1 Gen 1” and “USB 3.1 Gen 2.” Often, OEMs will add the speeds (5Gbps and 10Gbps, respectively) to their spec tables as a handy reminder for consumers. (SuperSpeed USB +, we hardly knew ye.)

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