The motherboard is the main circuit board connecting all of the components of your PC together. Because of its role as the central connection point, the motherboard plays a big role in determining how many other devices you can attach as well as how well they perform. A motherboard with plenty of expansion slots and available ports gives you room to grow and expand in the future.

Expansion slots are sockets built-in to the motherboard for plugging in new hardware. The type of slot determines the type of expansion card you can plug into it.

PCI slots
These can transmit data much faster than older slot formats, and are used for devices such as sound cards, video cards and network cards. Most hardware is compatible with these efficient slots, and if you are planning on upgrading in the future, you will want to have a few PCI slots available.

AGP
This is a special slot designed for video cards. AGP slots are designed for fast and direct communication between the video card and the processor, greatly increasing the performance of games- and graphics-intensive programs.

An interface port is a socket on the outside of the PC's case that allows you to connect external devices such as keyboards, mice, printers, scanners, digital cameras and joysticks. You can purchase circuit cards to add additional ports, but only if you have slots available and your motherboard supports this type of upgrade.

Keyboard/mouse port
Many systems have ports for plugging in a keyboard and mouse or other device.

Serial port
Serial ports can only accommodate one device at a time, and they're slow compared to USB ports.

Joystick/game port
These ports are now used for older joysticks and other gaming devices that aren't compatible with any of the newer interfaces.

USB 1.1
Most PCs come with at least one USB port. USB ports are the most popular type of port, and allow for high-speed communication (up to 12Mbps) between external devices and your computer. Printers, scanners, digital cameras and many other peripherals use this port. USB-compatible devices may be connected to your PC through the USB port on the back of the computer or through a USB hub.

USB 2.0
An upgrade of USB 1.1, USB 2.0 boasts a 480Mbps data transfer rate. USB 2.0, also called High-Speed USB, is compatible with CD and DVD drives, USB 2.0 features total backward compatibility with the older interface. The 2.0 interface requires a PCI adapter card for PCs, and a PCMIA card for notebook computers to allow for the massive amount of data transfer.

IEEE1394
It goes by several different names; Sony, for example, calls it i.Link™, and Apple calls it FireWire®. IEEE1394 ports and cables are designed to transmit images and video in a purely digital format between your system and other devices, such as a digital camcorders and cameras. This interface runs slightly slower than USB 2.0 at 400Mbps, but is essential for anyone interested in digital imaging applications.

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