USB 2.0, 3.0: Now, USB4 with Thunderbolt Technology

Jun 21, 2019 in 08:30 AM | Posted By Janelle W.
USB 2.0, 3.0: Now, USB4 with Thunderbolt Technology

There is a fair amount of confusion about the different types of USB ports and speeds. We've written a basic explainer on what the differences are between USB-A, USB-B (micro and mini) and USB-C. Click here to read more.

Where it gets confusing is the different generations of USB specifications.
While the A, B, and C designations are a connector type, 2.0, 3.0 (3.x Gen x, too) and now USB4 are generations of USB specs. Those generations establish specifications for connection, communication and power supply between computers and devices.

In basic terms:

  • USB 2.0 has a data transfer rate of 280 Mbit/second.
  • USB 3.0 has a data transfer rate ranging from 5 Gbit/second to 20 Gbit/second, depending on the generation.
  • USB4 will transfer at a rate of 40 Gbit/second.

In simplest terms, USB 3.2 was 10x's faster than USB 2.0. USB4 doubles the speed of that.

usb cables

USB-C and 3.0 are not the same

Many of people also conflate USB-C with USB 3.0 (or USB4). However, USB-C is JUST a port/connector shape. The USB generation inside the C port may just be 2.0 without any of the fun advantages faster transfer speeds and power supply capability of the later USB generations.

Put it this way. You may have a USB-C style connector that is just window dressing for a 2.0 connection. Which can become a problem. USB-C promoters talk about the faster speeds, charging power and two-way communication of a USB-C connection. But connect the wrong cable and a power surge could damage whatever is connected on either end of those cables.

The USB Implementers Forum is working on that. According to the non-profit organization that developed the Universal Serial Bus specifications, in January 2019 its USB Type-C„¢ Authentication Program was launched. It marked an important milestone for the optional USB security protocol.
Using this protocol, host systems can confirm the authenticity of a USB device, USB cable or USB charger, including such product aspects as the capabilities and certification status. All of this happens right at the moment a connection is made before inappropriate power or data can be transferred, according to the Implementers Forum website.


Then, in March, the Implementers Forum announced the pending release of USB4 specifications. The group tossed out its previous naming conventions (2.0, 3.x Gen x).

But the biggest change is the new specifications are based on Thunderbolt technology. We wrote some more about that here, too.