Data transfer speed

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Key points

  • Data transfer speed is the rate at which data can be passed from one device to another over an interface such as USB or Wifi.
  • Data transfer speed is an important measure because some applications will have a minimum data transfer speed for successful operation. * This effect is widely seen when streaming videos cannot obtain the transfer speed they need to stream faster than a video is playing.
  • New interface technologies increase data transfer speeds to make streaming of data more efficient. Data transfer is conventionally measures in bits per second rather than bytes per second (e.g. broadband is advertised as 8 megabits per second, which is 1 megabyte per second).


Examples of data transfer speeds

  • USB 2.0 has a maximum data transfer rate of 480 megabits per second.
  • A floppy disk drive's data transfer rate is 1 megabit per second.
  • A Blu-ray drive's data transfer rate is 576 megabits per second.
  • SATA 2.0, which is used to connect hard drives to computer motherboards, has a data transfer rate of 3000 megabits per second
  • Thunderbolt 2.0 can transfer data between devices at a rate of 20 gigabits per second
  • HDMI 2.0 transfers video data at a rate of 18 gigabits per second

Data transfer speeds are affected by interference from magnetic signals, bottleneck effects of other components in a system, status signalling and error correction.


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