What is USB4? How it Boosts Speeds, Supports Screens, and More

The USB or Universal Serial Bus was first announced back in 1996 and it has come a long way both in design and efficiency. The latest USB standard is known as USB4 which was announced in March 2019. A very long range of different versions paved the way for this powerful and feature-rich specification. 

In this article, we’ll discuss everything you need to know about USB4, how it’s better than other USB versions, and what benefits it brings to the table. It’ll clear all the confusions you have about USB4 and will allow you to utilize the maximum power it offers. 

What is USB4?

USB4 is the latest iteration of the USB protocol that combines the best features of USB 3.2 and Thunderbolt 3. It’s twice as fast as older USB versions because it leverages the Thunderbolt 3 specs. It offers greater bandwidth and also has a better ability to prioritize video and file data than all the previous USB versions. 

One of the best features of this new specification is that it offers backward compatibility. It means you can use your old cables and connectors and utilize their maximum potential if you connect them using USB4 connectors or cables respectively. 

It’s important to note that the term is written as “USB4”, not “USB 4” or “USB-4”. There is no spacing between alphabets and the number “4”. Keeping this in mind while searching on the internet will allow you to find the most relevant and satisfying results. 

USB4 Link with Thunderbolt 3

The Thunderbolt protocol was initially developed and released back in 2011 by Intel. It combines video and data signals into a single USB Type-C port and offers 40Gbps of data speed. There is a vast range of products available in the market that comes with the Thunderbolt 3 specification.

Thunderbolt 3 and USB4 come with identical physical connectors known as USB Type-C. This connector type offers a couple of benefits over the older big USB Type-A port. It can easily be installed in sleek and slim laptops and can be used from both sides. It means you can insert a USB Type-C cable into a Type-C connector either way without worrying about any up or down orientation.

USB4 Speed

As mentioned earlier, USB4 leverages the speed specs of the Thunderbolt 3 protocol and it’s capable of offering a speed up to 40Gbps. Impressively, it’s twice the peak speed of the previous USB version (3.2), which was 20Gbps. The following table will allow you to understand how USB4 is better than its previous versions. 

USB Versions: Comparison Chart

While the maximum speed that USB4 offers is 40Gbps, not all USB4 connections support it. Some USB4 connectors and cables can only transfer data at 20Gbps. These USB4 connections use USB4 Gen 3x1 mode and offer 20Gbps of bandwidth. 

So, it’s important to make sure that you see the specs of the device carefully to find out which USB4 model it offers. Every manufacturer will need to use any of the following logos to sell their products based on USB4 specifications. It’ll allow customers to determine the speed of a product before making their buying decisions.

Source: https://usb.org/sites/default/files/usb4_logo_usage_guidelines_april_2020_f_2.pdf

USB4 Transfer Data and Video Signals Simultaneously

One of the biggest and most notable features of the USB4 protocol is that it can transfer both data and video signals simultaneously. Moreover, the latest USB specification also comes with the “protocol tunneling” capability. This feature allows this port to adjust the available resources in a smart way if it’s transferring both data and video signals. 

For example, if you’re using a USB4 connection that can support 40 Gbps of bandwidth, and you have connected it to an external monitor. In addition, you’re also using the same connection to copy data using your external drive. Let’s suppose that the video signal that you’re using needs 10 Gbps of bandwidth. In such a scenario, your USB4 connection will automatically allocate the remaining 30 Gbps of bandwidth to manage your data-copy function through an external drive. 

The USB4 protocol also offers an alternative mode that allows it to transmit HDMI and DisplayPort signals over the Type-C connection. It performs this by splitting up resources optimally for the best performance. 

This “alternative mode” is also present in the 3.x protocols but they fail to split data efficiently. For example, the alternative mode of DisplayPort can only split up resources on the basis of 50/50 between video and USB data. It means that USB4 specification is optimized and can offer more scalability between different types of applications.

USB Video Signal Management

As mentioned above, the USB4 supports the alternative mode. It allows the connection type to power high-resolution displays easily. When the USB4 works alone, it allows you to run an 8K resolution display at a 60Hz of refresh rate along with the HDR10 colors. 

However, when the signal works with the DP Alt More 2.0, it offers 80 Gbps of bandwidth in total. But you need to keep in mind that in this configuration the signal only moves in one direction. This configuration allows you to connect two different displays with 8K resolution at a 60hz of refresh rate. It also means that you can use up to four 4K displays with the USB4 at the same refresh rate

USB4 Supports USB PD (Power Delivery) 

Another great feature of the USB4 specification is that it supports Power Delivery with up to 100-watt speed. It means that a USB4 connection installed in laptops and computers will allow you to charge devices at high speed and you won’t need to worry about finding a wall outlet. 

Keep in mind that all the USB4 connection types must support power delivery. This rule is different from what we have for USB 3.2 ports where some of them offer Power Delivery and others don’t. If you have a laptop that offers a USB4 port with a lightning bolt logo, you can use that to charge your smartphone at full speed. 

In addition, the 100-watt charging speed isn’t only enough for smartphones but it can also charge tablets and many laptops easily. Keep in mind that the PD specification allows the USB4 port to deliver only the amount of power that your device needs. It means that if your iPhone needs to be charged at 20-watt the USB4 PD will allow it to deliver only 20-watt. Therefore, you won’t need to worry about overloading or overheating the battery of your device. 

USB4 Backward Compatibility

We have already mentioned that the USB4 is backward compatible. It means that the latest specification can work with all the USB 2 and USB 3 ports and devices. However, you need to keep in mind that if you use any older port or device with a new USB4 device or port, you’ll get the capabilities and speed of the older protocol. 

For instance, if you hook your USB4 device to a USB 3.2 or USB 2 port, it won’t be able to provide you with 40 Gbps of bandwidth. However, backward compatibility comes in handy because it allows you to keep using your old cables and devices with the new ones. It is one of the best features of the latest protocol that not only saves money but also keeps countless devices and cables from going obsolete. 

Keep in mind that companies always need time to apply the new requirements. Furthermore, in order to benefit from quicker transfers, both ports in the connection must support USB4 protocol, not simply the cable. So, if you buy a device with a USB4 connection type, you may need to upgrade other pieces of equipment as well. 

USB4 and the Emergence of Thunderbolt 4 

It’s important to discuss the emergence of the Thunderbolt 4 protocol by Intel as it’s already available in the market. These are two different standards but they’re not competing with each other. A device that comes with the Thunderbolt 4 capability is certified by Intel for USB4. It means that it supports all the functionalities that the USB4 offers including the support of the Thunderbolt 3 protocol.

So, if you see a product available in the market that shows Thunderbolt 4 label, it means that it has USB4 certification and will offer 40Gbps of speed. It’ll also have backward compatibility and will support Thunderbolt 3 devices as well. Therefore, it’s safe to say that “Thunderbolt 4” is like a branding program for USB4. It shows that a device is based on the latest specification and supports all the top-end features. 

USB4 Products in the Market

There is a range of products available in the market that come with USB4 support. The new Apple MacBook Pro and MacBook Air come with this specification. However, you need to keep in mind that buying these devices doesn’t mean that you’ll enjoy the maximum 40Gbps of speed using all your existing peripherals and cables. 

Your old devices will be able to connect with your new laptop with a USB4 connection, but they will be limited to the maximum speed/bandwidth of the older USB specification they support. Additionally, manufacturers don’t need to pay royalties to Intel in order to manufacture devices with the USB4 specification. Not only does it increase the likelihood of the USB4 specification’s widespread adoption but it can also reduce the cost.

However, making USB4 devices compatible with the Thunderbolt 3 protocol isn’t mandatory for manufacturers. It means that you can buy a laptop from the market that comes with USB4 specifications but doesn’t offer the maximum 40 Gbps of bandwidth. 

Final Words

The USB4 protocol combines the advantages of all prior USB standard development with the addition of Thunderbolt protocols. It comes with compatibility with older USB standards and cross-platform support for Thunderbolt devices. All device makers are now allowed to manufacture products with USB 4 specifications without paying royalty to Intel. 

It is accelerating the global adoption of this technology rapidly. We hope this guide will allow you to understand the latest USB4 protocol in detail and will help you choose the products with the right connection type based on your needs.