Memory is where the CPU stores and retrieves program instructions. It plays a role in how fast a computer runs and what a consumer can do with it.

The most important types of computer memory to understand when helping customers select a computer are:

  • RAM (Random Access Memory.): This is the part of a computer's memory in which temporary data is stored. When the computer is turned off, information stored in RAM is erased.
  • Hard Disk Drive: This is the part of a computer's memory that stores permanent information in the form of files. To erase information from the hard disk, it has to be deleted. The hard disk has a greater storage capacity than other types of permanent memory and is relatively inexpensive. It is generally used in desktop computers and laptops.
  • Flash Memory: This memory chip is used in smartphones, tablets, MP3 players, digital cameras and other portable devices instead of a hard disk. Some netbooks, laptops and desktops also use Flash memory. A Flash chip stores memory even when the power source is turned off. It is smaller and quieter than a hard disk and accesses memory faster. The drawback is that it is more expensive and doesn't have as much storage capacity as a hard disk.

RAM, hard disk, flash and file sizes are all measured in bytes. One megabyte (MB) is one million bytes; one gigabyte (GB) is one billion bytes; one terabyte is one trillion bytes. To give some perspective, a music file is about 3MB, a movie about 2GB.

The larger the hard disk drive or flash memory, the more information and programs the computer can store. The larger the amount of RAM, the faster the computer will run, since RAM supports the processor speed by storing temporary instructions for quick access as programs run.