PCI stands for Peripheral Component Interconnect, which is an industry-standard, high-speed bus found in nearly all desktop computers. It is a hardware interface for connecting peripheral devices to a computer. PCI slots allow you to install a wide variety of expansion cards, including network cards, sound cards, graphics cards, controller cards, RAID cards, modems, and scanners. PCI automatically configures cards to work properly with other PCI cards in any computer. PCI cards come in both 32-bit and 64-bit versions, as well as both 33 MHz and 66 MHz speeds. Running at 32 bits and 33 MHz, PCI yields a throughput rate of 133 MBps. PCI Express (PCI-E) is the next evolution of PCI that uses existing PCI programming concepts and communications standards but improves the performance to match the increased speeds of modern computers. PCI Express doubles the data transfer rates of the original PCI bus. PCI Express supports the same types of expansion cards as PCI and was designed to be backward compatible with standard PCI cards, thus allowing you to continue using any existing PCI cards. However, standard PCI cards would still perform at the regular PCI speed.
In summary, PCI is a hardware interface for connecting peripheral devices to a computer, and PCI slots allow you to install a wide variety of expansion cards. PCI Express is the next evolution of PCI that improves the performance to match the increased speeds of modern computers and supports the same types of expansion cards as PCI.
