Expansion slots provide a connection for a number of devices and functions. To add features to your computer, you can typically add a peripheral card to an existing bus slot. The following table lists common expansion buses in a PC system:
|Peripheral Component Interconnect (PCI)||PCI supports a 32- or 64-bit I/O bus providing compatibility with both 486 and Pentium machines.
|Mini-PCI||Small form factor computers, such as laptops or micro-ATX systems, might include a mini-PCI slot. Mini-PCI devices are small cards with either 100- or 124-pins. A typical use for a mini-PCI slot is to add internal cards (such as wireless cards) to laptops.|
|Peripheral Component Interconnect Express (PCIe)||PCI Express (PCIe) is a next generation I/O bus architecture. Rather than a shared bus, each PCIe slot links to a switch which prioritizes and routes data through a point-to-point dedicated connection and provides a serial full-duplex method of transmission.
|Accelerated Graphics Port (AGP)||AGP is similar to PCI, but designed specifically for graphics support. Motherboards that provide AGP support have a single AGP slot. AGP is commonly used for video cards in modern computer systems, but is being replaced by PCIe. AGP slots are typically brown.|
|Audio Model Riser (AMR)||A riser card is not a bus, but rather a card that attaches to the motherboard and allows inserting additional cards (called daughter cards). AMR slots typically provide sound or modem functions.|
|Communications Network Riser (CNR)||CNR is a riser card slot (not a bus) that allows for inserting networking, wireless communication, sound, or modem functions.|