The ubiquitousness of USB means that everyone and their uncle has encountered this connector at some point. Flash drives, computer peripherals, phone chargers – they all use USB, and no connector has ever been as popular as USB. So, the name – Universal Serial Bus – is quite fitting.
But as it usually goes, there are always numbers, different versions, and compatibility issues involved with evolving technologies. When USB is concerned, you’ll encounter USB 2.0, USB 3.0, and USB 3.1 fairly commonly, with USB 3.2 slowly rolling out and with USB4 set to be implemented in the future.
In this article, however, we’ll be focusing specifically on USB 3.1 Gen 1 and Gen 2, taking a closer look at what makes these seemingly identical connectors differ from one another.
A Brief History Of USB
The original USB 1.0 connector was first introduced in 1996, created as a result of the joint efforts of seven big IT companies: Compaq, IBM, DEC, Intel, Nortel, NEC, and Microsoft. Just as the name implies, the Universal Serial Bus was introduced because of the need for a simple universal connector that would simplify connectivity across a wide array of devices.
Obviously, it succeeded. The implementation of USB made the lives of hardware manufacturers a lot easier, not to mention how much it helped the average PC user who was not overly familiar with all the different ports and connectors that were in use at the time.
The original USB connector supported data transfer speeds of up to 12 Mbit/s and various revisions followed over the years, enhancing data transfer speeds with each new iteration. And while the signature USB Type-A connector remained the most widespread, a vast variety of other connectors with different pin configurations were also introduced over the years. These included Types B and C connectors, along with Mini and Micro variants of Type A and B connectors.
But we won’t delve too deep into that here. Rather, let’s get to answering the titular question, shall we?
USB 3.1 was released in 2014 and it offered 10 Gbit/s transfer speeds, twice what its predecessor – USB 3.0 – could manage, and it still used the same 9-pin USB Type A and Type B connectors, along with the less widespread Micro B connector. But what’s more notable about USB 3.1 is that it marked a departure from the simple and linear numerical naming scheme.
This brings us to Gen 1 and Gen 2. While this might imply that USB 3.1 Gen 2 is a newer revision of USB 3.1, that’s simply not the case. What it comes down to is essentially the following: USB 3.1 Gen 1 features the same SuperSpeed transfer mode seen in USB 3.0, while USB 3.1 Gen 2 features a new SuperSpeed+ transfer mode.
Gen 1 vs Gen 2 - What's The Difference?
Now that the labels are out of the way, what are the real differences between USB 3.1 Gen 1 and USB 3.1 Gen 2 i.e. the differences between SuperSpeed and SuperSpeed+?
As mentioned above, USB 3.1 mostly uses the same 9-pin connector as USB 3.0, so there are no backward compatibility issues to worry about – USB 3.0 and USB 2.0 are both supported. Ultimately, it mainly comes down to speed – Gen 1 supports speeds of up to 5 Gbit/s, just like USB 3.0, while Gen 2 supports speeds of up to 10 Gbit/s.
So, SuperSpeed and SuperSpeed+ are simply marketing terms tied to the aforementioned data transfer speeds. The latter does use a more advanced 128b/132b encoding scheme, but that is not something that the average PC user needs to concern himself/herself about.
Moving Forward - USB 3.2 and USB4
The USB technology is by no means done advancing – USB 3.2 was released in 2017, and with another big speed boost came another big labeling mess.
USB 3.2 came in four “flavors”:
- USB 3.2 Gen 1×1 – 5 Gbit/s transfer speed using 8b/10b just like USB 3.1 Gen 1 and USB 3.0
- USB 3.2 Gen 1×2 – 10 Gbit/s transfer speed with old 8b/10b encoding (USB-C only)
- USB 3.2 Gen 2×1 – 10 Gbit/s transfer speed like the USB 3.1 Gen 2, with new 128b/132b encoding
- USB 3.2 Gen 2×2 – 20 Gbit/s transfer speed using 128b/132b encoding (USB-C only)
Now, USB 3.2 heralded a big change – it started phasing out the signature Type A connector (along with other types of connectors) in favor of USB-C. This was only natural, seeing as the new connector supported higher data transfer speeds, could charge peripherals faster, plus it is more convenient to use since it can be plugged in either way, just like Apple’s Lightning connector.
Coming up next is USB4, which will offer unprecedented 40 Gbit/s data transfer speeds, Thunderbolt 3 compatibility, and it will use only the USB-C connector. However, USB4 devices aren’t here yet, and they won’t be for a while.
The Bottom Line
So, the bottom line when it comes to comparing USB 3.1 Gen 1 and Gen 2 connectors: it’s all mostly about speed. A Gen 1 connector can support speeds of up to 5 Gbit/s while a Gen 2 connector can support speeds twice as high – a hefty 10 Gbit/s.
They are backward compatible with USB 3.0 and USB 2.0, and they support Type A, B, and C type connectors, along with the less popular Micro B connector.
The only thing that’s quite nasty is the nomenclature:
There are only iterations of USB between USB 2.0 and USB 3.2, but we have more than two terms that we use here. We can either make the distinction between USB 3.0 and USB 3.1 or between USB 3.1 Gen 1 and USB 3.1 Gen 2 (in which case, USB 3.0 doesn’t exist).
Only the USB Implementer’s Forum may know why it had to be like this, but thankfully the issue does turn into just a mild inconvenience once you manage to wrap your head around it.