Glossary · Hardware

USB (Universal Serial Bus)

USB is a standard for connecting peripherals and storage to computers, covering data transfer, power delivery and connector shapes.

Updated October 6, 2026

USB (Universal Serial Bus) is a standard for wired connections between computers and devices such as keyboards, drives, phones and chargers. It defines the data signaling, power delivery and connectors.

Why it matters

USB speeds vary by version: USB 2.0 is 480 Mbit/s, USB 3.2 Gen 1 is 5 Gbit/s, Gen 2 is 10 Gbit/s and USB4 reaches 40 Gbit/s. Marketing names are confusing, so check the actual speed in the spec.

USB also carries power, from 2.5 W on classic ports up to much higher levels with USB Power Delivery.

Example

USB 2.0:  480 Mbit/s  = about 60 MB/s theoretical
USB 3.2 Gen 1: 5 Gbit/s = about 625 MB/s theoretical

Copying a 10 GB file over USB 2.0 takes minutes longer than over a 5 Gbit/s port, even with the same drive.

Common mistakes

  • Assuming a blue or USB-C port is automatically fast. Check the version.
  • Using a cheap cable that supports only USB 2.0 speeds or low power.
  • Mixing up the connector shape with the protocol version.

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