Since USB 3.0 opened the era of high-speed transmission in 2008, USB interface technology has undergone several iterations and now finally ushered in a milestone upgrade - USB4. This new specification released at the end of 2019, after more than three years of ecological construction, is reshaping the way devices are connected with revolutionary transmission efficiency and compatibility.
Technology evolution: from a single protocol to ecological integration
The core breakthrough of USB4 lies in its multi-protocol integration capability. Through tunneling protocol technology, USB4 encapsulates USB 3.2, DisplayPort and PCIe protocols into a unified data packet to achieve synchronous transmission of data, video and peripherals. This means that only one USB-C cable is needed to complete the graphics rendering of an external graphics card, the data throughput of a high-speed solid-state drive, and the video output of a 4K display, completely breaking the limitations of the single function of traditional interfaces.
In terms of transmission speed, USB4 starts at 20Gbps. Currently, mainstream products have achieved 40Gbps bandwidth, and in the future it can be upgraded to 80Gbps through PAM3 encoding technology. This leapfrog improvement not only meets the needs of real-time 8K video transmission, but also makes it possible for the continuous read and write speed of external storage devices to exceed 5GB/s.
Core advantages: speed, compatibility and intelligence
The ultimate form of one cable for multiple uses
USB4 continues the design of USB-C connector, but completely releases its potential through protocol optimization. With 40Gbps full-duplex transmission capability, one cable can simultaneously complete laptop charging, dual 4K display expansion and multiple peripheral connections. Taking MacBook Pro as an example, the USB4 interface can achieve 100W power supply, 8K video output and high-speed data synchronization, significantly improving office efficiency.
Breaking the Thunderbolt monopoly
USB4 has ended the long-standing confusion of interface standards by being compatible with the Thunderbolt protocol. Device manufacturers can produce accessories that support Thunderbolt functions without paying patent fees, and users can also clearly identify device performance through the unified USB4 logo. For example, a cable marked "USB4 40Gbps" indicates that it supports Thunderbolt 4-level transmission capabilities.
Intelligent dynamic allocation mechanism
USB4 introduces intelligent power management and dynamic bandwidth allocation technology. When the device is connected to the docking station, the system will automatically identify the type of peripherals and prioritize bandwidth allocation to high-priority tasks. For example, the PCIe channel bandwidth is automatically increased when an external graphics card is connected, and the voltage and current are dynamically adjusted during charging to ensure stable operation in multi-tasking scenarios.
Ecological application: from professional fields to consumer electronics
The popularity of USB4 is reshaping the form of devices:
Professional creation: The 80Gbps version can support 8K@60Hz video transmission. With PCIe tunnel technology, external GPU workstations become a reality
Mobile office: With 140W PD power supply, thin and light notebooks can achieve all-day battery life without carrying a power adapter
Smart home: USB4 cables that support 120Gbps asymmetric transmission can achieve low-latency data interaction between AR glasses and the host
Storage revolution: The continuous read and write speed of external NVMe solid-state drives exceeds 4GB/s, surpassing the performance of most built-in hard drives
Future outlook: A new-era of 80Gbps and 240W
According to the USB-IF plan, 2025 will usher in the full popularization of USB4 2.0. By then:
80Gbps transmission: Real-time transmission of 8K@120Hz video is achieved through the new PAM3 encoding technology
240W power supply: Supports 48V/5A ultra-fast charging to meet the power supply needs of gaming laptops and professional workstations
Smart cable ecosystem: E-Marker chip will realize real-time monitoring of cable status and automatically adapt to device needs
