USB name confusion continues – DER SPIEGEL

When Apple released its new MacBook and Mac Mini with its own M1 processor in mid-November, a notable feature was the integration of USB-C sockets with Thunderbolt. This quick interface is standard on Apple, but close with co-developers Intel Connected – Apple has moved away from supporting its own ARM processors.

USB-C Ports குறிப்பிட Thunderbolt / USB4 as referred to was very surprising: to Apple It has already integrated Thunderbolt 4 or USB 4 in its first CPU development step – that is, the latest revisions of two specifications, which are not even a year old? Looking at the data sheet reveals: yes and no – followed by a thick “but”.

Like the previous Mac, the new M1 Mac can handle the Thunderbolt 3, and the USB 3.1 host controller for General2 data transfers is up to 10 Gbit / s. However, on the motherboard, you can find the JHL8040R components, which Intel refers to as the “Thunderbolt 4 Redeemer”. Such reducers improve signal quality, but have no protocol logic: they rely on Thunderbolt logic on the SoC processor (or elsewhere). The tenth generation of Core i processors includes Thunderbolt 3 logic, while the recently launched Eleventh Core i generation includes the new Thunderbolt 4. Thunderbolt 3 logic in the Apple M1 Sosi. Above all: Thunderbolt 3 and Thunderbolt 4 have identical user data rates of 40 Gbit / s, so Thunderbolt 4 offers no advantages in this regard – the same Redeemer chips work for both.

Name confusion

The fact that there is no new speed limit is the reason why further development of Thunderbolt has been discontinued as a separate standard: Intel has sent the specification to the USB Standard Group USB-IF, which has upgraded to USB4 – known from Thunderbolt Together, but the new maximum data rate for USB is 40 Gbit / s. USB-IF has changed some technical nuances, which is why pure Thunderbolt 3 controllers are not fully compatible with USB4. The attentive reader will be compelled to ask a question at this point: Why does Apple advertise M1-Mac’s USB-C sockets with USB4?

This is because all manufacturers can specify in their data sheets which USB modification they tested for connections accordingly – and not the maximum speed that the ports provide. Although a new speed level is added with each (secondary) modification of the USB standard, all previous levels are compatible downwards – the so-called generations. USB 3.0 General 1 came with speeds of up to 5 Gbit / s, while USB 3.1 added 10 Gbit / s sister Gen2. The less common USB 3.2 20Gbit / s replacement came with the Gen2X2, while the 40GB / s level derived from Thunderbolt, combined with USB4, is officially known as General3X2. Without the “General” specification, it is not possible to reliably tell what speed a USB socket provides.

Death blow

USB-IF request c’t request, as announced in the request, if the minimum speed of at least 10 Gbit / s General-2, first introduced with USB 3.1, is on board, then this is the USB-4 specification Enough. It is already known that you do not need to support Gen 3×2 – but this does not apply to Gen 2×2. Above all: the Gen 1 replacement USB 3.0 speed (5 Gbit / s) is not enough – at least as a design goal for developers. Related devices certainly run backwards compatible in this mode, and the 5 Gbit / s level is generally a technical low, for example, if the connected cable is too bad for 10 Gbit / s performance.

Introduced with USB 3.2, the 20 Homit / USB is even better at homeopathy sizes, practically taking a death blow as it sits between chairs: 10 Gbit / s installed is even higher for USB sticks and companies. Enough; On the other hand, if maximum speed is important, something at 40 Gbit / s will be faster.

Therefore, it can be accurately written that the sockets on the Apple M1 Max’s data sheets have been checked for compliance with the latest USB-4 standards, although they only offer the 10 Gbit / s speed limit introduced six years ago with USB 3.1. Additionally, there is 40 Gbit / s – but it is not compatible with the brand new USB 4, but via the relatively old Thunderbolt 3. Since USB 3.1, the confusion over names has worsened with each USB fix.

You cannot assume that identical USB information is present on similar devices that appear at the same time. In addition to the M1 Mac, the new PlayStation 5 and Xbox Series X / S game consoles will also appear these days. Sony USB 3.2 speaks to General 2 and his data sheets Microsoft USB 3.1 is subject to speeds of 1. from General, which means that Sony already offers up to 10 Gbit / s with USB 3.1 (but USB 3.2 to 20 Gbit / s is not USB ) And Microsoft developers use the original USB 3.0 speed of 5 Gbit / s (instead of the 10 Gbit / s USB that came with the 3.1 fix).

White Knight

How does Thunderbolt 4 fit into the picture? Well, Thunderbolt has always provided more than just USB data transfer: it can also be used to convert PCI Express or monitor signals to external devices. All of these are included in the USB 4 specification – but like the new speeds, not mandatory, but optional. In addition, the terrain has been expanded: with the Thunderbolt 4, as with USB hubs, signal distribution is possible, and device chains (daisy chains) are no longer available.

The classic Thunderbolt 3 has become a subset of the USB4 standard. So the new Thunderbolt 4 standard does not bring much speed, but acts as a savior in naming confusion: it builds on USB 4 and forces additional options into the USB universe. In addition, the minimum requirements have been increased – for example, two 4K monitors can be controlled. This was also possible via Thunderbolt 3, but only the 4K screen was mandatory. Apple claims that the M1 Max can run on 6K screens, but says nothing about dual-monitor capabilities.

Apple may have such a taste for advertising without mentioning “Thunderbolt / USB4”, i.e. without the number after Thunderbolt. More precisely the Thunderbolt 3 will be with better screen support than the one provided with 3. quality and USB 3.1 speeds – it is not too big and modern. Thunderbolt 4 is currently only found on expensive notebooks with the Eleventh Core i generation. Implementing Thunderbolt 4. However, Intel also took the path of minimal resistance: as the measurements show, the previous Thunderbolt 4 notebooks did not have 20GB / s USB, but only the well-known 10GB / USB.

Overview

Since Thunderbolt basic technology is now available to all USB-IF members, this is only a matter of time before other manufacturers and suppliers use their own control processes. This only applies to manufacturers of USB-4 or Thunderbolt-4 docks and hubs (none yet), but of course other CPU providers. AMD. After all, 40 GBit / s USB would not be bad for Raison processors, although such integration is at least until 2022. Apple has already made further progress and is already offering the integrated Thunderbolt with its first internal SoC! The fact that the “only” Thunderbolt 3 was initially planned is practically irrelevant: with the Thunderbolt 4, there is no higher maximum speed, only greater flexibility and extended downward compatibility.

The growing USB name confusion from USB 3.1 is growing: in the future there will be plenty of notebooks and other devices with USB-4 sockets, from which the top 10 Gbit / s will come. If you want to ensure high speeds, the preferred display signals come from the socket, and you can connect a USB-C power supply, as usual you have to trust the more expensive devices with the Thunderbolt logo.