Everything You Need to Know About USB 4
USB 4 – or USB4 as it’s officially called – is on the technology horizon, and like Wi-Fi 6E or mobile 5G , you’ll likely have a lot of questions about what the new USB standard means for many of your devices. So let’s take a quick look at everything we know about the upcoming USB4.
It’s a big upgrade for speed and bandwidth
USB4 is supposed to be twice as fast as the current USB 3.2 standard (20Gbps), which means it will support a maximum speed of up to 40Gbps in most cases. (Your actual speeds will obviously depend on which devices you are using.)
USB cables use two “lanes” to send and receive signals from connected devices. However, some devices may be able to replace the USB4 cable with unidirectional delivery. For example, DisplayPort 2.0 “Alt Mode ” will increase the available signal bandwidth to 80 Gbps, enough to support 8K HDR video monitors and other high-speed devices over USB4. Dual-lane shipping also means that some USB4 devices will support Intel and Apple’s Thunderbolt 3 standard, although this varies by manufacturer.
Speaking of allocating more bandwidth, USB4 also supports the USB PD charging standard, which means your smartphones and other devices will be able to charge much faster over USB4 – provided they’re built to support fast charging , that is.
USB4 devices can support three maximum speeds: 10Gbps, 20Gbps, and 40Gbps. In other words, make sure you go through the specs of the device to get an idea of its maximum supported speed, if that matters most to you when you buy, say, a new laptop (or hub).
And there is another speed-related feature that Tom’s Hardware describes really challenges USB4:
Much of the USB 4 specification is the ability to dynamically adjust the amount of resources available when sending video and data over the same connection. So, let’s say you have USB 4 with a maximum speed of 40Gbps and you are outputting to a 4K monitor while copying tons of files from an external SSD. And let’s make a reservation that the video stream requires about 12.5 Gbps. In this case, USB 4 will allocate the remaining 27.5 Mbps to your backup drive.
USB4 will be backward compatible
USB4 cables will use Type-C connectors, a flat port with rounded corners found on most smartphones and laptops today.
You should be able to plug a USB4 cable into just about any USB Type-C port, but it won’t always work the same way. For example, the speed of a USB4 cable will drop when plugged into an older port, while older USB Type-C cables plugged into a USB4B 4.0 port will by default use the highest possible baud rate (but cannot reach the same speed. As a cable USB4).
Likewise, you may need an adapter to use USB4 cables with USB Type-A ports that you usually see on a PC.
Why “USB4?”
According to Brad Saunders, CEO of USB Promoter Group , the “USB4” branding was chosen to avoid confusion caused by the gradual update of previous USB standards, ie “USB 3.1” and “USB 3.2”. It is also possible that USB4 could be renamed, or that further updates – for example, what would otherwise be called “USB 4.1”, will see clearer naming differences, even though technically still “USB4”.
When will USB4 appear?
The first USB4 cables and devices are expected to arrive around the end of 2020, but 2021 is probably more likely at this point. This is partly because USB4 will cost more to manufacture than older USB types. And we’re kind of in the middle of a global production halt / slowness / hell, which doesn’t help speed up USB4 startup at all.