You all know the USB interface, they are available on every laptop, desktop PC and almost every multimedia-capable device such as game consoles, digital cameras and smart TVs. In short, USB is the standard to connect peripheral devices to your computer.
In the meantime, however, the USB world is no longer as easy as a few years ago. The interface is consistently further developed and according to USB 3.2 USB4 (according to the official spelling) has now taken over the baton.
What makes USB4 so special?
In addition to a significantly higher speed, the latest iteration of the USB standard also has various other special features:
- Twice as fast:While the maximum theoretical speed at USB 3.2 was still 20 GBit/s, up to 40 Gbit/s are now possible at USB4. With USB4 2.0 there are even up to 80 Gbit/s.
- USB-C connection:Various types of plugs were used for the standard in front of USB4. These include the variants type A, type B, mini-USB and micro USB. With USB4 there is only the USB Type-C connector.
- Downward compatible:USB4 offers high compatibility with previous USB versions up to at least USB 2.0 and with Thunderbolt 3.
- Efficient transmission:With USB4 it is possible to efficiently transmit various data and display protocols via a bus. In addition, the tunneling technology for PCI Express, DisplayPort and host-to-host broadcasts is supported.
| USB 3.2 | USB4 | |
|---|---|---|
| speed | max. 20 GBit/s | max. 40 GBit/s (80 GBits/s bei USB4 2.0) |
| Support plugs | USB-A, USB-B, Mini-USB, Micro-USB. USB-C | USB-C |
| Display Support | Usually a 4K monitor | Up to two 4K monitors or an 8K monitor |
| Daisy Chaining | Is not supported | limited to certain Thunderbolt 3 functions |
| dynamic bandwidth adjustment | Fixed bandwidth assignment | Dynamic assignment for files, audio, video, etc. |
Differences compared to Thunderbolt
USB4 has a lot together with Thunderbolt, including the USB-C connector and the maximum speed of up to 40 GBit/s. This is also not surprising, because the current USB standard is based on the Thunderbolt 3 protocol.
To say that USB4 would only be Thunderbolt with a different name, but is too short. Especially compared to Thunderbolt 4 there are relevant differences:
- Higher minimum speed:Significantly stricter minimum requirements are planned for Thunderbolt 4. For example, the minimum speed for each connected device is 32 Gbit/s. In contrast, USB4 devices are allowed to work with at least 20 Gbit/s.
- Minimum performance requirement:USB4 devices require at least 7.5 watts for correct function, but a Thunderbolt-4 device requires at least 15 watts.
- Cable length:The speed of 40 GBit/s is guaranteed at Thunderbolt 4 on a cable length of a maximum of 2 meters, with USB4 the same speed can be transmitted to a maximum of 1 meter long cable.
- Power Delivery (PD):With PD, devices such as smartphones can be charged directly via a USB4 or Thunderbolt connection with high performance. With Thunderbolt 4, charging with at least 100 watts is guaranteed, up to 240 watts are possible. The cable must also be designed accordingly for an output of 240 watts. With special EPR cables, up to 240 watts can also be possible with USB4. It should be noted that not all USB4 devices support the high performance. However, there is no minimum requirement as with Thunderbolt in USB4.
Dynamic bandwidth distribution
The dynamic distribution of the available bandwidth is one of the most important features of USB4 and Thunderbolt. This makes it possible for different protocols such as PCIe, DisplayPort and USB data to be transmitted via the same cable, while the bandwidth is dynamically adjusted.
In the sum of its properties, USB4 represents great progress compared to its predecessors. It could be possible that at some point in the future there may only be an interface and that Thunderbolt will be completely in the USB standard. In any case, the basics for such a development are laid with USB.
