USB standards and specifications can be a bit confusing, especially with multiple updates over time. We’ll answer questions like the differences between USB 3.1 Gen 1 and Gen 2, explore why Gen 2 is better than Gen 1, and provide other useful information to help you understand various aspects of USB standards.
USB 3.0 was released in 2008, over a decade ago, as the third major revision of the USB standard. USB 2.0, released in 2000, had a transfer speed of only 480 Mbit/s. USB 3.0 brought significant improvements over USB 2.0. Since then, USB 3.0 has been further developed and is now referred to as USB 3.1 Gen 1. So, USB 3.0 and USB 3.1 Gen 1 are the same thing.
As the organization responsible for maintaining USB (Universal Serial Bus) specifications and compliance, USB-IF made this decision to make it easier for developers and manufacturers to access the same relevant information, ensuring proper development and backward compatibility of products. They also oversee naming conventions for USB cables and devices.
Comparison between USB 3.1 Gen 1 and USB 3.1 Gen 2: The only difference between USB 3.1 Gen 1 and Gen 2 is the speed. USB 3.1 Gen 1 supports a maximum speed of 5 Gbit/s, while USB 3.1 Gen 2 supports a maximum speed of 10 Gbit/s. USB-IF intended to use different names for USB 3.1 Gen 1 and USB 3.1 Gen 2, which would have been “SuperSpeed USB” and “SuperSpeed USB+” respectively, but this naming convention didn’t become popular in the industry. Typically, OEMs indicate the speeds of 5 Gbps or 10 Gbps on their specifications sheets to differentiate these USB standards. Others in the industry simply refer to them as “USB 3.1 Gen 1” or “USB 3.1 Gen 2.”
The Arrival of USB 3.2: Subsequently, USB technology continued to evolve and USB 3.2 was introduced in 2017. USB 3.2 has four different variants, each with its unique name and significance. The four variants of USB 3.2 are:
| USB 3.2 Gen 1×1 | USB 3.2 Gen 1×2 | USB 3.2 Gen 2×1 | USB 3.2 Gen 2×2 | |
| Transfer Speed | 5Gbps | 10Gbps | 10Gbps | 20Gbps |
| Former Name | USB 3.1 Gen 1 And USB 3.0 | — | USB 3.1 Gen 2 | — |
| Interface Options | USB-A、 USB-C、 micro USB | Only USB-C | USB-A、 USB-C、 micro USB | Only USB-C |
These variants offer different transfer speeds and interface options. With the advent of USB 3.2, the prevalent USB-A connection started to be replaced by USB-C. USB-C, due to its higher data transfer speed and faster charging capabilities, became the primary USB interface for utilizing USB 3.2 Gen 2.
Thunderbolt : Thunderbolt is a hardware interface brand developed by Intel® in collaboration with Apple® to connect peripheral devices to computers. Thunderbolt 1 and 2 used the same interface as Mini DisplayPort (MDP), while Thunderbolt 3 adopted the USB-C interface.
Next Up is USB4: The next development stage for USB technology is USB4. It offers a data transfer speed of 40 Gbit/s and is compatible with Thunderbolt 3, using only the USB-C interface. USB4 aims to increase bandwidth and focuses on the USB-C interface ecosystem while minimizing confusion for end users.
Key designs of USB4 include: Using a single USB-C interface for display, data, and power delivery/storage functions. Universal compatibility with existing USB and Thunderbolt products. Defining port capabilities for a predictable, consistent user experience. Enabling hosts to configure bandwidth, power management, and other performance-related parameters flexibly based on system requirements.
USB technology has made significant progress since its inception and will continue to evolve in the future. For USB 3.1 Gen 1 and Gen 2, the only difference is speed, and both are backward compatible with USB 3.0 and USB 2.0. With the release of new USB standards and USB-C, USB will see further improvements in the future.
