Don't know your RAM from your hard drive? We explain some commonly used terms?

MHz: Megahertz. One million cycles per second.

GHz: Gigahertz. One thousand-million cycles per second.

MB: Megabyte. Usually refers to amount of RAM or hard-drive space.

GB: Gigabyte. Usually refers to hard-drive space.

RPM: Revolutions per minute. Refers to hard-drive speed.

CPU: Central processing unit, also called the processor or chip.

Memory: Your computer has two types of memory: long term (hard- drive) and RAM, which stores information only when the computer's power is on.

HDD: Hard disc drive. The central storage area of your computer.

RAM: Random access memory.

SDRAM: Synchronous dynamic random access memory.

RDRAM: Rambus dynamic random access memory.

DDR RAM: Double data rate random access memory.

CD-R: Disc drive capable of reading CDs and copying (burning) data to "write-once" CDs.

CD-RW: Disc drive capable of reading CDs and copying many times to "rewritable" CDs.

DVD-R: Disc drive capable of reading CDs/DVDs, and copying data to "write-once" DVDs.

Bus: The highway on which data travels within a computer.

AGP: Accelerated graphics port. A dedicated slot on the motherboard for the 3D graphics card.

SCSI: Small computer system interface. A port for attaching drives and peripherals, now uncommon.

PCI: Peripheral component interconnect. A port for attaching components. Still used, mainly for internal modems and sound cards.

USB: Universal serial bus. A very common port for attaching peripherals such as scanners, digital cameras and printers.

FireWire: A very fast port, often used for transferring data from a video or digital camera.