PC motherboard expansion slots throughout the years
PC Motherboard Flexibility
Motherboards are the main part of any PC, that everything else has to plug into. Its the only part of the PC that means you have to have a big case. However the motherboard is what allows you to plug in specifically made components that perform specific tasks. This is really the whole purpose of a computer. Some of the more common components that people plug into their motherboard are the usual sound, and video cards. However some people, especially engineers and scientists use components that aren't available to the general public. You can even build your own components that you can use to complete whatever function you want. The exact part of the motherboard that allows us to do this is the expansion slots. These are the motherboard, and the pc's connection to the outside world. As the technology of motherboards has increased, and the CPU's have become faster, expansion slots have also changed, and they have just as much an interesting story as the other parts of the pc.
Expansion bus slots
Expansion bus slots on the motherboard can be easily identified, as they are located close to each other and near the rear end of the case.
Peripheral Component Interconnect (PCI)
PCI slots are available in most computers these days, and are like the tried and tested expansion slots. These slots are used to connect PCI compatible cards. They are usually white and are about three inches long.
Accelerated Graphics Port (AGP)
AGP slots are used primarily to connect video cards to your PC. The AGP port allows the video adapter to communicate directly with the CPU. The AGP slot is usually brown, and almost is thought of as the competition to the PCI slot for graphics card specifically.
PCI Express (PCIe)
PCIe is available on most of the new motherboards. This slot was designed to replace the PCI and AGP slots. But most motherboards have PCI as well as PCIe slots. The PCIe has tried to catch up with the speed of the AGP graphics slot, that's why the amount of AGP graphics cards has declined, from a few years ago, when AGP was the buzzword.
Audio/Modem Riser (AMR)
AMR has 46 pins and is found on mostly really old motherboards. This slot is mainly used to separate analog devices, such as the modem,(yeah they are that old) from other digital parts on the motherboard.
Communications and Networking Riser (CNR)
CNR has 60 pins and is used to enhance the built-in capabilities of some of the older motherboards by allowing additional components to be added above the capabilities of the motherboard originally.
Industry Standard Architecture (ISA)
ISA is the oldest type of expansion slot on motherboards, and most of the time, you won't find it in today's motherboards. This black-colored slot is long in shape and has two parts one small and the other long.