USB 3.1 Gen 2 Features: Speed, Power, and Compatibility

USB 3.1 Gen 2 is a specification of the Universal Serial Bus (USB) interface standard, representing a high-speed data transmission protocol that significantly enhances the data transfer rate and performance of USB devices. It is an important iteration in the evolution of the USB 3.x family, also known as SuperSpeed+ USB 10Gbps.

Key Technical Specifications

Data Transfer RateThe theoretical maximum data transfer rate of USB 3.1 Gen 2 reaches 10 Gbps (gigabits per second), which is twice that of USB 3.1 Gen 1 (5 Gbps, originally named USB 3.0). In practical applications, the actual transfer speed is approximately 1.2 GB/s (gigabytes per second) (considering encoding overhead and other factors).
Encoding SchemeIt adopts the 128b/132b encoding method, which has a lower overhead ratio (only about 3% overhead) compared to the 8b/10b encoding used by USB 3.1 Gen 1 (20% overhead). This improvement further optimizes the effective data transmission efficiency.
Power DeliveryIt is compatible with the USB Power Delivery (USB-PD) standard, supporting up to 100W of power supply (20V/5A) when used with appropriate cables and devices. This enables fast charging for laptops, tablets, and other high-power electronic devices, as well as power supply for peripheral equipment.
Backward CompatibilityLike other USB standards, USB 3.1 Gen 2 is backward compatible with USB 3.1 Gen 1, USB 2.0, and USB 1.1. Devices and cables of lower specifications can work with USB 3.1 Gen 2 ports, but the data transfer rate will be limited to the lowest supported specification of the connected device.

Physical Interfaces and Form Factors

Type-AThe traditional USB Type-A interface (standard USB port) is still widely used in desktops, laptops, and peripheral devices (such as external hard drives, USB hubs). USB 3.1 Gen 2 Type-A ports are usually marked with a teal color inside the port for identification.
Type-CThe USB Type-C interface, with its reversible plug design, has become the mainstream form factor for USB 3.1 Gen 2. Most modern smartphones, laptops, and tablets use USB-C ports that support USB 3.1 Gen 2, enabling both high-speed data transmission and power delivery through a single cable.
Type-BThe USB 3.1 Gen 2 Type-B interface is mainly used in professional equipment such as printers, scanners, and external hard drives, and is less common in consumer electronics.

Typical Application Scenarios

High-Speed Data StorageExternal solid-state drives (SSDs) with USB 3.1 Gen 2 interfaces can achieve fast read and write speeds, making them suitable for transferring large files (such as 4K video, raw image files, and large software installation packages) between devices.
Multimedia TransmissionIt supports the transmission of high-resolution video signals (such as 4K/60Hz) when combined with protocols like DisplayPort Alt Mode over USB-C, enabling the connection of laptops to external monitors or TVs through a single USB-C cable.
Peripheral ConnectivityHigh-bandwidth peripherals such as professional cameras, external graphics cards (eGPUs), and docking stations rely on USB 3.1 Gen 2 to ensure stable and fast data transmission, avoiding latency and bottlenecks in data transfer.
Fast Charging and Power SupplyWith USB-PD support, USB 3.1 Gen 2 ports can provide fast charging for devices such as MacBook, iPad Pro, and flagship smartphones, and can also power small desktop devices (such as mini PCs) without the need for an additional power adapter.

Naming Clarification

It is worth noting that the USB Implementers Forum (USB-IF) later revised the USB naming convention:

USB 3.1 Gen 2×2 (20 Gbps, dual-lane transmission) was renamed to USB 3.2 Gen 2×2.This renaming often leads to confusion in the market, but the technical specifications and performance of USB 3.1 Gen 2 itself remain unchanged.

USB 3.1 Gen 1 (5 Gbps) was renamed to USB 3.2 Gen 1.

USB 3.1 Gen 2 (10 Gbps) was renamed to USB 3.2 Gen 2.