Thunderbolt 3, USB-C, USB 3.1: What you need to know

The computer connection is in full upheaval. A few months after the infancy of the USB-C and the USB 3.1, Intel has unveiled the Thunderbolt 3 … which uses the USB-C connector and encompasses the USB 3.1. Is it already confusing? This is just the beginning. We are focusing on these technologies that are being brought to the next standards.


USB Type-C connector (USB-C)


Reversible, tiny, that makes “click” when you plug it in. No, we are not talking about the Lightning connector of the iphone and the ipad, but of the USB type-C. The commonalities between the two are not fortuitous, Apple has largely influenced the creation of the new USB connector.


With a thickness of 2.6 mm and a length of 8.4 mm, the USB type-C (which is shortened to USB-C) has been designed to replace the other types of USB connectors that have made their time.


The USB type-A, the most common in computers (hence the fact that it is sometimes referred to as the “standard” USB), is relatively imposing at the time when laptops are increasingly fine. The USB micro-B (or “micro-USB”), the one that equips all the smartphones except the iphone, is small but inconvenient and fragile. You never know which way to connect the cable. In short, the USB-C is the solution to all these problems.


A solution all the more interesting that this new connector can do much more than its predecessors. As already explained in a previous article, it supports the USB power Delivery 2.0 standard (it can deliver a maximum power of 100 W, what to power any laptop), the USB alternate mode (it can pass a DisplayPort 1.2 signal) and the USB 3.1, which dramatically increases the throughputs compared to the usb2.0.


This support for USB 3.1, as welcome as it may be, causes some confusion. Because the USB-C and the USB 3.1 have arrived at the same time, this may lead to the idea that both are inseparable, but this is not the case. USB-C is not necessarily synonymous with USB 3.1.


The most telling example is certainly the USB-C cable sold by Apple (€35). It uses a USB-C connector at each end, but only supports the USB 2.0 standard. During a transfer, the 480 Mbit/s cannot be exceeded. The Anker accessory manufacturer will, it, release a USB-C cable to USB-a limited to USB 2.0. In the future, however, USB 3.1 should be imposed. Finally, it remains to be known which …


The USB protocol 3.1 (Gen 1 and Gen 2)


Indeed, there is not a USB 3.1, but two. There is the USB 3.1 Gen 1 and the USB 3.1 Gen 2. The first allows a maximum throughput of 5 Gbit/s, while the second doubles the throughput to reach up to 10 Gbit/s. In fact, the body in charge of USB standardization decided that the USB 3.1 Gen 1 was the new name of the USB 3.0.


The MacBook 12″ is equipped with a USB-C port supporting USB 3.1 Gen 1 (up to 5 Gbps, therefore).
It’s more complicated than the mention of “USB 2.0 port” that was used not so long ago to describe the connection of a Mac and that did not leave room for (almost) no doubt about the performance and type of connector, but it will have to be done.


Not to mention that there is another subtlety; The USB 3.1 (Gen 1 as Gen 2) also works with the USB-a connector. It is therefore quite possible that a data transfer made with the USB-a connector is faster than with new USB-C hardware, because the first one would support the USB 3.1 Gen 2 and not the second. It will therefore be necessary to scrutinize the technical data sheet of the products before moving on to the cashier, on pain of finding itself bridled.


Thunderbolt 3, which encompasses USB-C, USB 3.1 and other protocols


Above all this, the Thunderbolt 3 arrives. But it is already worth remembering what the Thunderbolt is at the base. Created by Intel and Apple, it is a highly efficient multi-protocol connection that allows you to chain devices.


Its first generation, inaugurated in 2011 with the MacBook Pro 15, allows a maximum throughput of 10 Gbit/s for data Transfer (PCI Express protocol) and the management of a screen 2 560 x 1 600 to 60 Hz (DisplayPort 1.1 protocol). Two years later, the Thunderbolt 2 multiplies the data transfer rate by two and opens up to 4 K screens thanks to the support of the DisplayPort 1.2. These two generations use a mini DisplayPort connector.
The Thunderbolt 3, which has just been announced and which will point the end of its connector at the end of the year, allows to do more, and not just a little bit. The maximum flow rate is increased to 40 Gbit/s. With this double bandwidth, it allows you to manage two 4 K monitors at 60 Hz or a 5 K multi panel display with a single cable (always with the DisplayPort 1.2). The 5 k monitors composed of a single panel will not be compatible on the other hand, fault with the lack of support for DisplayPort 1.3. But a screen like The Dell UP2715K, which is made up of two panels 2560 x 1440 pixels set side by side, should be managed a priori.
All this is already very appreciable, but the biggest novelty of Thunderbolt 3, it is undoubtedly its use of the USB-C connector with the support of USB 3.1 (Gen 1 and 2). In other words, when a USB-c/3.1 device is plugged into the Thunderbolt 3 port, it will work.
The ability to deliver a maximum power of 100 W is also supported. So we can recharge a portable Mac with its Thunderbolt Port 3.
With adapters, you can even use the HDMI 2.0 (4 K screen at 60 Hz) and 10 Gbit/s Ethernet. At the end of the day, Thunderbolt 3 is the universal connection that has been waiting for so many years.
The subtleties of Thunderbolt 3
While the first two generations of Thunderbolts require active cables, which contain a controller and other chips, the Thunderbolt 3 works with passive cables, less sophisticated and therefore cheaper … but limiting the throughput to 20 Gbit/s.
There will actually be two different types of Thunderbolt 3 cables:
Active cables, supporting Thunderbolt up to 40 Gbit/s and USB 3.1
Passive, less expensive cables supporting Thunderbolt up to 20 Gbit/s, USB 3.1 and DisplayPort 1.2
It is also necessary to mention the optical cables, planned in a second time, which will be distinguished by their length (up to 60 meters, against 2 meters for the others).
For a computer to be able to support Thunderbolt 3, it will need the Alpine Ridge Controller. Given the release period — the end of the year — concurrent with Thunderbolt 3 with the next generation of Intel processors, the issue of its exclusive integration with Skylake has arisen. Intel finally indicated that Alpine Ridge was a stand-alone chip. Manufacturers will therefore have the option to add Thunderbolt 3 compatibility without changing the Broadwell processor (the current generation).
For the power supply, the 100 W only applies to the load. Otherwise, for bus-powered appliances, it is 15 W. This means that you will not be able to power a large external graphics card or some “heavy” raid systems with just a Thunderbolt 3 cable.
What about the Thunderbolt 3 in the Macs?
What’s apple going to do with Thunderbolt 3? Questioned by Ars Technica, a spokesperson a — unsurprisingly — kicked in touch: “We are not talking about possible things to come.”
Therefore, we can only speculate on what awaits us in the coming months. It will not have escaped anyone that two products that make intensive use of Thunderbolt have not been updated for a long time.
The first one is the Thunderbolt display. It was launched in 2011 and has not evolved since (aside from its price which increased from €150 in March). result, it is exceeded technically: definition of only 2 560 x 1 440 pixels, 1st generation Thunderbolt and USB 2.0 ports.
Thunderbolt 3 opens up a very interesting outlook for the next version (if there is one). Of course, you can imagine a 4 K screen, or even 5 K (5 120 x 2 880), like the retina imac. The hub aspect would be put to the liking of the day with USB-C/3.1 ports.
The Mac Pro has not been renewed since late 2013, while newer processors and graphics cards have been available for months. Apple may be waiting for the Thunderbolt 3 to update it. The Thunderbolt occupies a central place in the Mac Pro that puts all the above to extend its capabilities. The transition to the third generation is therefore a planned and logical evolution.
Logically, it would also be in the MacBook Pro. It was this machine that inaugurated the first generation thunderbolt in 2011 and then the Thunderbolt 2 in 2013. Thunderbolt 3 ports would replace most of the current ports advantageously.
However, unlike the MacBook, you should not expect a drastic slimming cure thanks to the USB-C connector. With its core i5 or i7 processor (and a dedicated graphics card for the most expensive model), the MacBook Pro absolutely needs a fan, which limits a possible reduction in its thickness.
The MacBook, it, has already made a part of the way, since it integrates a USB-C port. But in its current version, it will not be able to enjoy the Thunderbolt 3. It only supports USB 3.1 (Gen 1) and does not have the famous Alpine Ridge controller required for Thunderbolt 3.
It is important to understand that if the Thunderbolt 3 integrates the USB 3.1, the reverse is not true. A USB 3.1 device plugged into a Thunderbolt 3 port will work. A Thunderbolt 3 device plugged into a USB 3.1 port will not work. The products and the Thunderbolt Connector will be recognizable by their lightning-flash logo.
Is the lack of Thunderbolt 3 on the first generation MacBook a hard blow? Not necessarily. Of course, one would not complain about having more functions if they were there. “Who can do the most, may the least,” as they say.
But in the case of the MacBook, Thunderbolt 3 is not necessarily a relevant technology. The MacBook Pro 15 with dedicated graphics card already barely manages a 5 K screen (it is connected with two Thunderbolt 2 cables). It’s not with his integrated graphics card that the MacBook would do the trick.
The compatibility with the first two generations of thunderbolt (with an adapter) is interesting, but then again, the MacBook is not the most suitable machine to take advantage of Thunderbolt devices that are for most professional products.
Moreover, Intel still introduces the Thunderbolt 3 as a thought-for-productivity connection (it could also translate “productivity” to “performance”). The USB will remain the most common solution for the general public, the market to which the MacBook is directed.
For this reason, we may think that Apple will not immediately embed the Thunderbolt 3 in all its machines. As much as the Thunderbolt 3 seems almost inevitable in the next Mac Pro and MacBook Pro, it’s much less obvious for the MacBook Air.
The MacBook Air is now becoming the new non-retina MacBook Pro 13: An affordable machine that has a foothold in the past. It still does not have a Retina display and was not entitled to the Force Touch trackpad during the spring update. Moreover, it was only this year that he passed to Thunderbolt 2. If Apple continues in the same way, it will not have Thunderbolt 3 on its next renewal.
As for the adoption of Thunderbolt 3 on the PC market, which has remained hermetic to the first two generations, the fact that it uses the USB-C connector could make things easier, but there are still barriers to the extra cost for controllers and the very restrictive license program of Intel.

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