What’s The Difference Between USB-C, and Thunderbolt 3?

The new iMacs and MacBook Pros have confused me enough with all these new connectors, that I thought I’d try and make some sense out of it.  Here is what I found out:

USB Type C really describes a connector plug shape:

USB Type C USB Type B USB Type A

There are a couple other variations, especially on the USB-B shape as well.

Even though Apple’s Lighting port connector looks similar to USB Type-C, it is completely proprietary to Apple.

The default protocol for the new USB-C connector is USB 3.1, which has a maximum speed of 10 Gbps (Gigabits per second).  This is the same speed as Thunderbolt 1.

However, USB Type-C ports can support a wide variety of protocols such as DisplayPort, VGA, HDMI, and others.

What is Thunderbolt 3?

Thunderbolt 3 is a superset of capabilities that run on USB-C connectors and cables.  It is a different protocol than USB 3.1:  It is capable of 40 Gbps and can supply as much as 100 watts of power.  It’s meant to be a single cable solution to move a large amount of information up to and including two 4K displays.  It is bi-directional with four lanes of PCI Express Gen 3 and eight lanes of DisplayPort 1.2.

Not all USB Type C Ports Support Thunderbolt 3

Mobile devices like smartphones and tablets may use the connector, but the Thunderbolt platform is only available on Intel processors and most mobile devices don’t have Intel inside.

So if you plug a USB Type C device into a Thunderbolt 3 port, it will work but won’t support all of the Thunderbolt features.  Similarly, a Thunderbolt 3 peripheral plugged into a regular USB Type C port will work but won’t support Thunderbolt features.

Here is a great reference for more information:



Thanks also to these web pages for the information: