The Universal Serial Bus, or USB connector has been a mainstay of a wide range of devices for years, though the actual port used and cable required, could vary dramatically. USB4 could change that by adopting many of the best features of Intel’s Thunderbolt 3 standard. USB4 will be faster, better equipped, and perhaps even more standardized across the industry than every type of USB that came before it.
While we wait for supporting devices to show up though, you might want to wrap your head around USB 3.2. It’s more confusing than USB4 will be.
USB4 was announced in March, 2019, with a rough outline of its features and capabilities. What we haven’t been given yet, is a full breakdown of USB4 specifications. The USB4 standard is currently in the “final stages of review,” according to a statement from the USB Promoter Group released in March, 2019. The full specification is slated to be released sometime in mid-2019.
As for products that support USB4, its backwards compatibility (see below) means that there are already existing products that will work with it. For USB4 certified devices though, we could be waiting until the second-half of 2020 before they start to become available.
The most immediate benefit of USB4 is how much faster it will be than its predecessors. Where the USB 3.2 2×2 specification can only transfer data at up 20 Gbps (gigabits per second), USB4 will be capable of up to 40 Gbps. That’s also four times the speed of the far more common USB 3.1 (3.2 gen. 2) and eight times as fast as USB 3.0 (3.2 gen. 1).
The speed of USB4 also matches Thunderbolt 3’s, which is an important factor in the development and planned future for the USB standard.
USB4 will be built around the USB-C connector, so will be entirely reversible — no more flipping back and forth like you had to do with USB-A cables. It will also be able to offer charging and power delivery up to 100 watts, so USB4 will be perfectly capable of charging your laptop, or powering your monitor.
That combination of high data throughput and power delivery means it will be able to act as a singular cable for displays. It will be able to handle two 4K displays or one 5K display over a single connector. It will also have enough data throughput to connect external graphics cards to desktops and laptops.
USB4 will also be backwards compatible with USB 3.x, 2.x, and 1.x devices. You might just need to change the cable you connect those devices with.
Although not a feature for USB4 itself, one of its greatest improvements could be greater standardization. The USB Implementers Forum (USB-IF), the group that manages the promotion and marketing of USB, hopes that it can use the new USB generation to make the standard more uniform across devices. With a singular connection type in USB-C, there won’t be a wide array of potential cables or ports. The USB-IF will also create a standard feature list which it will push manufacturers to support with USB4 devices. That will be a stipulation of certification, although it will not be mandatory, and as an open standard, USB4 can be implemented by any manufacturer in any fashion they choose.
It’s not clear yet whether confusing naming conventions used with the USB 3.x generation of ports will continue, but from the outset, USB4 will be the singular name used for such devices.
What about Thunderbolt 3?
If all the features and performance numbers for USB4 sound a lot like Thunderbolt 3, that’s no coincidence. Although both USB and Thunderbolt 3 have coexisted for four years, they haven’t been interchangeable in most cases. USB4 will change that, to a certain degree. Thunderbolt 3 and USB4 should support one another in almost every way. While they will continue to exist as separate entities, USB4 and Thunderbolt 3 ports and devices should be compatible with one another across the board.
That said, at this time, with no official specification for USB4, we can’t say for sure whether it will exactly match the capabilities of Thunderbolt 3. While in theory it should be capable of things like handling external graphics cards, Intel has made it clear that that’s a Thunderbolt 3 feature for now. Likewise, Thunderbolt 3 is capable of creating a 10Gb Ethernet connection between computers, which there has been no mention of with USB4 so far.
Time will tell whether USB4 will be able to offer the same sorts of features, but in the short term it may be that Thunderbolt 3 remains the more comprehensive standard.
One difference between the two technologies that we know for sure will remain, though, is that that Thunderbolt 3 requires certification where USB4 will not. USB4 is also an open standard where Thunderbolt 3 isn’t, so we could see a much wider array of USB4 devices in the future, all of which should work with existing Thunderbolt 3 ports and devices.
While the confusion over which is which may continue with the launch of USB4, it won’t matter as much, since everything that supports one should work just fine with the other.