However, every peripheral component that is constructed for use with a particular type of data bus still needs to connect to that type of internal expansion slot or external expansion port on your computer. In other words, if you have a system that does not have an AGP slot, you cannot plug in a AGP-specific device.

Sometimes you can attach a component that uses a type of data bus your computer system normally doesn't support. This is accomplished through the use of a controller card, which acts as an interface for different data bus standards.

For example, say you have a USB-compatible printer that you want to use with your computer, which only supports the parallel connections. You can plug a USB riser/controller card into an PCI-compatible internal expansion slot, and then plug the USB-compatible printer into the controller card. Voila! Now, you can use that printer.

Be aware that SCSI controller cards can be PCI-compatible. That means you need to get an SCSI controller card that will fit into the type of internal expansion slot you have on your motherboard.

It's also important to keep speed "bottlenecks" in mind. A computer is only as fast as its slowest connection. This means that a busy component connected to a slow data bus will perform poorly, even if you have a very fast CPU inside your computer.