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What Is a PC Bus? A Basic Definition

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A PC bus, also referred as "the bus," is the path on the motherboard a PC uses to transfer data to and from the CPU and other PC components or other PCs. This includes communication between software. For example, a PCIe (peripheral component interconnect express) expansion card, such as a graphics card (aka GPU aka video card), will send data to and from PCIe bus. 

There are numerous types of buses to accommodate different technologies. Below is a list of common computer buses:

  • eSATA (External SerialATA) - for transferring data between external hard drives and disk drives
  • PCIe - for accessing PCIe expansion cards and certain M.2 SSDs 
  • SATA (Serial ATA) - for accessing internal storage drives. Slower than PCIe 
  • Thunderbolt - for accessing peripherals
  • USB - for accessing peripherals

This article is part of the Tom's Hardware Glossary.

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Scharon Harding

Scharon Harding is a Senior Editor at Tom's Hardware. She has a special affinity for gaming peripherals (especially monitors), laptops and virtual reality. Previously, Scharon covered business technology, including hardware, software, cyber security, cloud and other IT happenings, at Channelnomics, with bylines at CRN UK.