USB4 vs. USB-C: What’s the Difference?

USB4 vs. USB-C: What’s the Difference?

USB technology has had a naming convention problem for some time, and the latest releases have only gone part of the way to clearing that up. USB4 might be a fresh start, but it still uses the USB-C connection, and there are still plenty of older, non-USB4 USB-C connections to contend with.

It’s perfectly understandable to be confused by USB standards. Their speed, cable header, and features can vary dramatically from generation to generation, and device to device. But if you’re wondering how USB4 vs. USB-C matches up, then we’re here to help you out. Here’s everything you need to know about these two important USB standards, and how you might be set to use them in the future.

Is USB4 the same as USB-C?

The short answer is no, but the longer one is: it’s complicated. Generally speaking, USB4 refers to the generation of USB technology you’re dealing with, and that mandates the maximum performance you can expect with a particular USB port, while USB-C relates to the type of connector it uses.

There have been USB 3 USB-C cables and headers, USB 3 USB-A cables and headers, and there are USB4 USB-C cables and headers. USB-C is one of the connector types that USB4 can be used with, but just because a cable or port is USB-C, doesn’t mean it’s necessarily USB4. In fact, unless it’s a very new device with a very new port, it’s probably not USB4.

However, USB4 does need USB-C, so while not every USB-C device is USB4, every USB4 device will use USB-C. As time passes and the USB4 standard becomes more commonplace, too, USB4 and USB-C will become the dominant type, and then they are a little more interchangeable, at least colloquially.

What is USB4?

What is USB4? 

USB4 is the latest specification of USB technology from the USB Implementers Forum (a non-profit group of companies that oversees USB development and marketing). Originally debuted in 2019 and based on Intel’s Thunderbolt 3 protocol, USB4 is designed to deliver greater data rates than any USB 3 generation, with better support for higher wattage USB power delivery, as well as tunneling of DisplayPort (up to the latest version 2.1) and PCI-Express, supporting connecting external displays and graphics cards to a range of devices.

The maximum data rate for USB4 is technically 40 Gbps, as with Thunderbolt 3 and Thunderbolt 4. However, this will only be possible on select USB4 devices and isn’t mandated. Instead, the minimum data rate for a USB4 cable or port is 20 Gbps. It retains backward compatibility with USB 1, 2, and 3 devices and ports, though may need an adapter in some cases.

Unlike USB 3 cables, however, which can use USB-A or USB-C connectors, USB4 can only use the reversible USB-C connector type. While this does mean that it is directly incompatible with a host of older USB devices which will need an adapter or converter to become compatible, it gives USB4 direct compatibility with Thunderbolt 3 and Thunderbolt 4 connections and cables.

That’s not to say USB4 can guarantee Thunderbolt 4 data rates of 40 Gbps, but a USB4 cable can be used with a Thunderbolt connection, and vice versa.

USB4 does, however, guarantee USB Power Delivery as a feature, which was optional with older USB 3 standards. USB4 must, at a minimum, guarantee a 7.5W power delivery per port, but the theoretical limits of USB4 power delivery are extremely high. With support for Power Delivery 3.1, there are already USB4 connections that offer 240W power delivery for much faster charging of larger devices, like tablets and laptops.

In October 2022, the USB Implementers Forum detailed a USB4 2.0 specification, which would allow select cables to use a triple lane design to deliver data rates up to 80 Gbps. That’s an exciting prospect in its own right, potentially opening up USB connections to handle much more demanding use cases. It will also be a simple upgrade, with all existing 40 Gbps rated USB4 cables, able to hit the new 80 Gbps data rate without difficulty.

What’s intriguing about this, however, is that USB4 also has the potential to restructure its data transmission to weight one end of the connection, if desired. If data is flowing more heavily from one direction (say to transmit video data to a display) the USB4 2.0 cables can be allowed to transmit up to 120 Gbps in one direction, while limiting the other to just 40 Gbps. Intel has already begun showcasing these kinds of data rates in its latest Thunderbolt demonstrations, building on what USB4 has enabled to open up the future of high-speed data transfer.

For more information on USB4 and all of its exciting developments, take a look at our complete guide to USB4.

What is USB-C?

What is USB-C?

USB-C is a USB connector option for USB cables that is symmetrical and reversible; two features that USB users had been requesting for some time before the debut of USB-C. Its “C” designation relates to the rounded corners of the connector, giving it a C-like curve. The original USB-C specification was published in 2014, with compatible devices following along a few years later.

USB-C features 24-pins, enabling both its reversible function, and the higher speeds of more recent USB standards, which require USB-C to function correctly.

While USB-C connectors are most commonly used in devices which offer higher-speed USB connections, USB-C offers no performance guarantees itself. It is relatively independent of the connection’s transfer specifications, which are instead designated by the connection’s numbering, such as USB 3.2 Gen 2x2, or USB4, for example.

USB-C doesn’t even provide a guarantee of any particular features, beyond being reversible. USB-C connections can offer USB Power Delivery for USB-based charging, and USB Alternative Mode, allowing for the transmission of video and data across the same connector, enabling external displays to connect to a device with a single cable. In more niche cases, USB-C also supports Audio Adapter Accessory Mode, whereby it is able to manage audio devices like headphones and headsets through a 3.5mm to USB-C adapter or converter. This can be used in conjunction with a USB-C charge-through port on the adapter, which allows power to charge the device at the same time as audio data is transferred through it.

The most common USB-C connectors at the end of 2022 are USB 3.2 Gen 2x2 USB-C cables, however, there are also USB-C cables that are only compatible with USB 2 data rates, and offer no shielding, or support for higher “Superspeed” data rates, nor USB alternative modes, or USB Power Delivery.

Many of the latest USB devices, however, support the USB4 standard, with USB-C connections. Apple devices have been some of the earliest proponents of the technology, combining USB4 and Thunderbolt 4 support on a wealth of its latest devices, including the MacBook Pro and MacBook Air M1 and M2 devices.

Although the first USB-C specification was published over eight years ago, it has continued to be developed and iterated upon in recent years. There were revisions of the original USB-C specification in 2015, 2016, 2017, 2019, and 2021, each introducing minor changes to the design. The most recent addition, however, introduced support for Extended Power Range, potentially enabling devices to pull as much as 240W from a single USB-C connection. This could be used by future devices to fast charge quicker than ever before.

USB4 vs. USB-C: Key Differences

USB4 and USB-C are two of the most important USB technologies today and will continue to be so for the next few years, but what are the USB4 vs. USB-C differences?

Fundamentally, they are two different aspects of modern USB connections that enable the high-speed, high-functionality, featureful USB connections that we use today. USB-C connections make using USB so much easier, with the reversible connections making it quick and simple to plug in and remove a USB connection, without having to guess which way around it goes. USB-C also opens up more pins for the new SuperSpeed standards that USB 3.2 Gen 2x2, and more recently, USB4, bring to the table.

USB4, on the other hand, is the standard that’s truly taking USB into the future and making sure it can compete with the likes of Intel’s Thunderbolt. While both technologies may use USB-C connections, Thunderbolt was, until recently, far faster and more capable than more traditional USB connections. With USB4, though, they’re near feature and performance parity, with the best USB4 cables able to offer the same high power delivery and high data rate connections as Thunderbolt 3 and 4.

It’s closer to Thunderbolt 3 cables than it is to Thunderbolt 4, but with full support for USB4 within the Thunderbolt 4 protocol, and full support for Thunderbolt 3 within the USB4 standard, there’s enough inter-compatibility that the two seem destined to merge over the coming years.

With its ease of use and ability to expand USB’s feature set, USB-C seems likely to remain the standard connector for USB for the foreseeable future. It will certainly remain the connector for choice with the new USB4 2.0 specification that the USB Implementers Forum has so recently debuted. That will mean that someday the USB4 vs. USB-C debate will see some USB-C cables offering greater data rates than USB4 because they’re USB4 2.0 USB-C cables.

Learn more about USB-C

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