USB 3.2: cables, names, speeds ... everything you need to know about the new standard

The USB 3.2 has just been announced: the new standard makes the paper explode throughput rates up to 20 Gb / s. In fact, and probably just to annoy the entire planet, the USB-IF decided that under this name would actually hide three protocols at different transfer speeds, USB 3.2 Gen 1, USB 3.2 Gen 2 and the USB 3.2 Gen 3. Standards that can pass through cables compatible with USB A or USB C connectors, which may be difficult to identify ... Here's all you need to know.

The USB IF has just formalized in February 2019 the USB 3.2 standard. A new chapter in the history of USB, since the cables compatible with different generations of USB 3.2 will reach theoretical maximum speeds of 20 Gb / s. Or the same transfer speed as the Thunderbolt 2 - the Thunderbolt 3, currently used as USB transfer protocol type C by some manufacturers reaches 40 Gb / s is twice this speed. The problem is that under the name USB 3.2 are hiding three generations each capable of different rates. These rates can be identical to those allowed by the USB 3.0 and 3.1 standards. Finally, the USB 3.2 standard is a transition standard between several USB connector formats and the USB type C connector that will eventually replace all.

USB 3.2 Gen 1, 2 and 2 × 2: theoretical rates

On paper, the USB 3.2 allows theoretical data rates up to 20 Gb / s. In fact, the USB-IF has actually announced three standards in the standard, only one of which can achieve this speed. To add a little more to the confusion, the generations 1 and 2 allow to reach the same speeds as the USB 3.1 Gen 2 (10 Gb / s) and the USB 3.0 also known under the name USB 3.1 Gen 1 (5 Gb / s). Thus with USB 3.2 we have the following three standards and theoretical rates:

    USB 3.2 Gen 1: 5 Gb / s
    USB 3.2 Gen 2: 10 Gb / s
    USB 3.2 Gen 2 × 2: 20 Gb / s

USB 3.2: cacophony of names

For this generation, we can not say that the USB-IF was simplistic. Not to say that the consortium has somewhat complicated things. In addition to the version names attached to their generation, the USB-IF recommends to the manufacturers the following trade names:

    SuperSpeed USB (USB 3.2 Gen 1)
    SuperSpeed USB 10 Gbps (USB 3.2 Gen 2)
    SuperSpeed USB 20 Gbps (USB 3.2 Gen 2 × 2)

The problem is that manufacturers have no obligation to use either of these names. So we can expect that some are trying to blur the tracks by announcing for example a compatibility "USB 3.2", suggesting speeds of up to 20 Gb / s when in fact it is only about USB 3.0 port rebranded to USB 3.2 port. In addition, if the names SuperSpeed USB 10 Gbps and 20 Gbps have the merit to say clearly what they consist, one wonders why the USB-IF did not follow the same convention with SuperSpeed USB. Again this may imply for the consumer speeds of up to 20 Gb / s when in fact it is only 5 Gb / s maximum.

Cables problems

To make matters worse, we must see that the USB 3.2 can pass through several different cables: USB A, microUSB or USB type C. It is therefore imperative to ensure that the cable you plug is compatible with the generation of the protocol that you aim to avoid lower rates. The multiplicity of generations and appellations of this standard, in addition to the creativity of the manufacturers in terms of designations around this standard, should not make the choice always very simple for the consumer.

Will USB 4 be more readable?

Presumably, yes. The USB 4 has already been announced, and this time it is to create a free version of the protocol Thunderbolt 3 (40 Gb / s), to reduce the license costs of manufacturers and therefore democratize this technology. The USB 4 will be backward compatible with USB 3.2, USB 2.0 and Thunderbolt 3, just as the USB 4 protocol will be backward compatible with Thunderbolt 3. This means that the Thunderbolt 3 cables can be used on USB 4 ports. conversely at 40 Gb / s. But we are not yet safe from a surprise ...

USB 3.2: why it's so complicated

This is the big question that many readers are asking themselves. Why for example, do not simplify, and talk about USB 3.0 (5 Gb / s), USB 3.1 (10 Gb / s) and USB 3.2 (20 Gb / s), as the transfer speeds of generations 1 and 2 correspond to those of the two previous versions? We know that in the past, the USB-IF had already made name changes that some will find absurd, such as renaming a posteriori USB 3.0 USB 3.1 Gen 1. There is no explanation. Especially since other consortiums just as important as the WiFi alliance, do just the opposite, and have simplified their nomenclature with WiFi standards 1 to 6 instead of less mnemonic networks 802.11a / b / g / n / ac / ax etc ...

Since the consortium is made up of representatives of the companies that use it, we can not help but think that it is precisely the latter that are driving this confusion. What move their devices for newer products: imagine for example an external disk manufacturer to pass a model designed when the output of USB 3.0 for a model USB 3.2. Which is technically true, provided you specify the generation somewhere. We can also imagine PC manufacturers enjoying it in the same way ... Of course, this kind of problem will undoubtedly occur more on the input and midrange devices - the good news is that when a product is compatible USB 3.2 Gen 2 × 2, so is it with all previous versions.