Why make it complicated when you can go to the simplest? This rhetorical question has undoubtedly greatly motivated the development of the USB4 standard!
Announced in 2019 and based on the Thunderbolt 3 protocol, the USB4 standard is fast approaching at the end of 2020. We are also starting to see it on certain products.
USB4: a simplified standard?
For those who don’t follow tech news closely, the arrival of a new USB standard may seem confusing. Rest assured, USB4 will not only allow better performance in terms of speed but will also greatly increase clarity.
USB4: a small revolution for the consumer
Fortunately, the USB Implementers Forum (USB-IF), an organization created by the founding companies of the USB protocol and in charge of its standardization, has worked to make all of this much easier for users.
First, that is the end of version numbers. Unlike the various USB 3.x standards, USB 4 will not engage in a maze of iterative nomenclatures (4.1; 4.2; 4.3, etc.)! It is for this reason that the name USB 4 is now written without space, unlike what we can read here and where we see that some still state USB 4 or USB 4.0.
In fact, while version numbers make life harder for users, they make sense to developers, but USB-IF wants equipment manufacturers (OEMs) to use simpler names when marketing products.
New logos to recognize USB4
It is also not excluded that the USB4 will evolve in the months and years to come; it is even very likely. Consumers will then be able to differentiate the different versions based on their data transfer speed, using the logo and a designation that includes speed.
The logos above show what to expect, for the standard itself, but also cables and connectors. Given the specifications of USB4, we will not be surprised to see an 80 Gbps USB4 logo appear in a few years!
However, be careful not to confuse this logo ensuring the presence of USB4 20 Gbps and all of its features, with that of USB 3.2 Gen 2 × 2 which allows a similar speed, but which does not take not support all functionality of USB4.
While choosing a cable could be a real headache, things are now much less blurry, which will also be an advantage when buying a laptop or motherboard.
USB 4: when and on which devices?
The deployment of USB4 is imminent, and in 2021 you will see a whole range of electronic devices equipped with USB4! It will not have been necessary to wait for 2021: at the time of writing, Apple has already launched its Macbook Air / Pro and Mac Mini and their new M1 chip with two Thunderbolt-compatible USB-C ports. / USB 4. Ditto for Intel since the first laptops equipped with 11th generation Intel Core processors and their Tiger Lake architecture support both Thunderbolt 4 and USB4.
What’s new with USB4?
Let’s take a look at the heart of the matter: what’s new in USB4, and what are the benefits for us?
» Maximum speed of 40 Gb/s: USB4 can operate, like Thunderbolt 3, at a maximum speed of 40 Gb/s thanks to the two-way operation of the USB-C cables. Certified cables, on the other hand, achieve a speed that goes beyond 40 Gb/s if we are to believe the USB-IF.
» Compatibility with many protocols: USB4 supports USB Power Delivery (up to 100 W), DisplayPort Alt Mode 2.0 and, optionally, Thunderbolt 3.
» Dynamic bandwidth sharing: USB4 allows tunnelling to transfer data transmitted via other protocols (USB 3.2, DisplayPort and PCIe) and manage the speeds allocated to these different sources. It thus manages to dynamically allocate a certain percentage of bandwidth to each of these sources according to their respective needs.
USB 4: USB Power Delivery
The great advantage of USB4 is to allow, using a single cable, to power your device, to pass audio and video signals, for example to a screen or from an external graphics card, but also to transfer data, all simultaneously. Accuracy is important, for the simple reason that not all USB-C connectors necessarily support USB Power Delivery.
It is now a requirement: USB4 devices with USB Type-C connectors must support the USB Power Delivery standard. USB4 specifications imply that Power Delivery can deliver power up to a maximum of 100W. Most devices, such as laptop power supplies, however, will not need to handle such power.
Compatible operating systems
We have just seen that on the hardware side, the CPUs under Tiger Lake and the Apple M1 processor under ARM use USB4. But what about the operating systems side?
To make a quick point, at the moment the very recent MacOS Big Sur has supported USB4 since its launch on November 12, 2020. On the Microsoft side, it is the version of Windows 10 20H2 that provides this compatibility. Finally, Linux is ahead of the game since the open-source operating system has supported USB4 since its update 5.6 released in March 2020.
USB4: USB-C connectors or nothing?
This is obviously not a surprise, and it is also good news: USB4 will only work on USB Type-C connectors, one connector to do almost everything! As mentioned above, USB-C is the only one to support USB Power Delivery, this standard being part of the specifications of USB4, so it makes sense to find this connector there.
What are the differences between USB4 and Thunderbolt 4?
There aren’t really that big differences between Thunderbolt 4 and USB4! In reality, Thunderbolt 4’s specification implies that it natively supports USB4.
There are, however, additional requirements with this new interface. Not all USB4-stamped devices will therefore be able to claim to be compatible with Thunderbolt 4. First, because they still need Intel certification, but also, because the minimum specifications of this new standard have been highly revised.
Intel, therefore, expects a minimum speed of 40 Gb/s and not 20 Gb/s, the minimum transfer speed required for USB4. Regarding the Thunderbolt 4 PCI Express link, Intel imposes a minimum bandwidth of 32 Gb/s, as well as DMA protection based on the Intel VT-d device. The table above is a good summary of what to expect from Thunderbolt 4 and its main differences from USB4.