What Is USB4? How the New Interface Boosts Speeds, Supports Screens, and More


Level 7
Aug 2, 2020
USB4, the next generation of USB, is in equal parts a reboot, a speedup, and a simplification of the everywhere-you-look connection spec. Here's what you need to know.

Picking Up Speed: A New Peak of 40Gbps​

One key thing to note up front: The USB Implementers Forum (USB-IF) styles USB4, indeed, as "USB4," with no space between the "USB" and the "4." We tell you this to potentially aid your online searches related to the term. If searching for the term "USB 4" term fails to turn up satisfying results, removing the space may help.
USB4 encompasses the Thunderbolt 3 specification, now matching that spec's top transfer speed, which is 40Gbps. That is double the peak speed (20Gbps) of the fastest, previous-generation version of USB, the dubiously named USB 3.2 Gen 2x2. That version of USB never got much uptake; only a few superfast external SSDs (like the Seagate FireCuda Gaming SSD and the SanDisk Extreme Pro Portable SSD v2) support it, and compatible USB 3.2 Gen 2x2 ports remain few and far between.
As a refresher on where USB has been, how the names have changed, and where it is going, here's a handy cheat sheet to all of the USB versions that remain relevant today in PCs old and new...

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