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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.

Further reading: