The technology industry has USB (Universal Serial Bus) As reference port for connecting peripherals and devices. Specially designed to save and standardize the connection of peripherals, it is present today in hundreds of millions of all types of electronic devices for connection, data transmission or power supply.

Since the launch of the first version in 1996, the USB-IF group responsible for the standard has been improving the standard in all its sections, from protocols to connectors, including the necessary cabling. Sections such as performance or compatibility were, of course, a constant driver of each version.

USB4 vs USB 3

The last version of the USB4 standard was approved in 2019, but only this year it began to be generally deployed in new generations of laptops, mobile phones or storage devices. We will check what the new interface has to offer compared to the previous versions.

Brands and nomenclature

When marketing is imposed on technology and the logic of things, something that unfortunately often happens in the technology industry, there are “attacks” against common sense, such as brand policies used to define different versions of a standard that has become necessary. in the field.

In addition to the interfaces or protocols (basically the method of data transfer) that defined the standard (USB 3.2 Gen 2 and Gen 1; 3.1, 3.0, 2.0…) it uses other names according to their maximum speed, which even if they are not part of the standard very confused. And then there are the connectors, there are up to six different ones, although this section is well resolved with the versatility that the USB Type-C connector has brought.

Starting with USB4, we’ll try to cut down on the chaos definition of brands more understandable for each user to avoid future confusion caused by incremental updates to previous standards. USB ports and cables are now labeled with a naming scheme that uses the syntax “USB XGbps”, where X is the transfer rate in Gbps. It is something…

Convergence with Thunderbolt

The main key and another difference between USB4 and USB 3 is convergence of the latest version with Thunderbolt. Originally designed by Intel as a proprietary standard, it is the industry’s next major interface for connecting peripherals and devices. Convergence is a (welcome) engineering effort to create a unified protocol capable of handling the enormous external I/O bandwidth requirements of future computer systems.

That way, and once Intel opened up the Thunderbolt specs and shared them with USB Promoter Group, all manufacturers can use the standard without paying license fees. This will increase compatibility between products and simplify the way devices, peripherals and equipment are connected. Intel has already announced the development of Thunderbolt 5, which will be matched by USB4 V2.

Connector type

The key difference between USB4 and USB 3 lies in their connectors. USB4 is the first major standard that for maximum performance requires the use of a specific connector for its operation, in this case the USB Type-C connector. Its smaller size and reversible design made it a great universal and multi-purpose connection system that the industry needed, both for data transmission and power charging in mobile and portable devices.

The USB 3 and older standard does not require the use of a single connector. Instead, it works with four different types, Type A, Type B, Micro B and Type C. The latter is technically the best and the one that should be heavily used on any type of device. Remember that USB Type-C supports a wide range of other protocols, allowing you to connect interfaces such as HDMI, DisplayPort, Thunderbolt and even a VGA analog video port. USB4 brings improvements in this area, especially with DisplayPort Alt Mode 2.0 created in collaboration between VESA and USB-IF.

Transmission speeds

We have already said that performance has been a factor of continuous improvement with each release. USB4 doubles the base bandwidth to 40 Gbps and uses multiple data protocols to make the most of the maximum available bandwidth at any given time. It must be mentioned here that USB4 devices will be able to support three maximum speeds: 10 Gbps, 20 Gbps and 40 Gbps, so the user will have to check the specifications of the specific device.

Note that the incremental update to USB4 (already announced by the USB-IF Group) doubles data transfer performance up to 80 Gbps thanks to a new physical layer architecture for use with both the new 80 Gb/s USB Type-C active cable and existing 40 Gb/s passive USB Type-C cables. And on top of that, you can increase up to 120 Gbps as the theoretical maximum transfer speed by taking advantage of Intel Thunderbolt 5 technical improvements.

Energy supply

USB is not just for data and connectivity. Energy charging is a section that also improves with each release. The first Power Delivery specification, USB PD 1.0, was able to deliver up to 100 watts using six fixed power profiles. Power Delivery 2.0 introduced more flexible rules and USB PD 3.1 increased the maximum amount of power that can be supplied via a USB cable at 240 watts.

Both USB4 and USB 3 support up to 240W power, as this is a feature of the USB Type-C connector, not the protocol. All the user needs is a quality cable. To say that there are differences in the minimum power delivered, even if they are negligible, 3 watts to 7.5 watts.

Backward Compatibility

Backward compatibility is important for a large standard like USB that has multiple versions active. Functional compatibility does not necessarily mean physical compatibility, as certain USB connectors are designed to connect to specific USB ports and cannot be used on other types. Rather it means one USB device will always be able to communicate with another once it is physically connectedregardless of generation.

Another issue is performance. You can use the latest generation of USB4 devices in a USB 2.0 port, but you will never have its maximum performance. In a peripheral like a keyboard or mouse, this is usually not relevant, but it is, for example, in an external SSD that needs access to the fastest interface it can support.

USB4 vs USB 3, included

The advanced features of USB4 and its recent introduction mean that cables and devices that offer it will be more expensive compared to USB 3. However, as USB4 becomes more widespread and manufacturing costs fall, it will certainly be as affordable as the previous rule. Remember that USB4 offers practically the same features as Intel Thunderbolt 4 and is much cheaper.