Thunderbolt 3 has been around for a bit now, giving Mac owners the ability to take advantage of transfer speeds up to 40Gb/s. USB4 will make that the default for the future of USB cables, too, in the near future.
Today, the USB Implementers Forum published details (via MacRumors) regarding USB4. The new specification was actually previewed back in March of this year, but only now getting published in this nature to lay the groundwork for what’s to come.
USB4 actually builds upon Thunderbolt, using it as the base to double the maximum bandwidth in the stock USB experience. Currently, USB is capable of 20Gb/s, but with USB4 that will jump up to 40Gb/s, effectively matching what Thunderbolt 3 can do right now.
USB4 will also offer backwards compatibility with Thunderbolt 3 and USB 3.2. Users will need certified cable to get the maximum 40Gb/s transfer speed. It will take advantage of two-lane operation using existing USB-C cables.
The USB4 specification will rely on the USB 3 connector, which means cable manufacturers will not have to change anything regarding ports on their devices. Finally, USB Power Delivery will be a requirement for devices built for USB4.
When will we see new products using USB4? Probably a year from now. But at least we know it’s on the way. Maybe by then we’ll get an iPhone with a USB-C port.