What is an Expansion Slot

Expansion slots are long, narrow connectors located inside the computer. An expansion slot allows you to insert an expansion card. Almost all personal computers except laptops contain (internal) expansion slots, which allow you to add more functionality such as memory, graphics cards, and support for special devices.

Expansion slots are located at the back of the computer, allowing more ports to be added to it.

Types of Expansion Slots

The types of expansion slots are:

ISA
ISA were the first standard for PCs, today they are considered old technology.

PCI
Peripheral Interface Controller operates at 33 or 66 MHz and 64 bits. These types of cards use parallel technology. In simpler terms, it uses an audiovisual interface that allows the computer to handle more functions.

PCI-X
PCI-X is the latest version of PCI technology operating at 66 MHz and 64 bits. It also uses parallel technology.

PCI Express
With fewer data channels, but much faster than AGP technology. PCI-Express is cheaper to design and build. It uses serial technology.

AGP
AGP was a slot designed for graphics cards. It was used on a motherboard that required high processing power for graphics.

AGP Pro
Used by Mac computers that require high redraw capability. A good example would be a PC running AutoCAD. Some slots require up to 110W of power.

AGP Pro slots had fewer data channels, but were much faster than AGP technology. This type of slot was much more upgradable and expandable. It also uses serial technology.