Computer memory stores data temporarily for rapid retrieval. When most computer users refer to the term, they are talking about the main memory of the computer. This is also called the random access memory (or RAM for short). However, memory chips of varying types are integrated into just about every electronic device you can think of, including coffee machines, microwaves, network routers, and cell phones.
The central processing unit--or CPU--of a computer works through a steady stream of data coming through the computer memory. The ability to store information in memory increases the overall speed of the computer, as retrieving information straight from the hard drive would take much longer. The more memory that a computer has, the better it will be able to handle processing larger amounts of data. Large memory reserves are beneficial for intensive application processing, games, photo editing, video editing, and complex modeling.
Computer memory is volatile. It relies on electricity constantly flowing through it at a controlled voltage in order to continue storing the memory. The computer both reads and writes new data into the memory at a constant rate, sending off data to the various components in the machine like the video card or network card.
When a person opens a picture file stored on his hard drive, what is actually happening is that the hard drive sends data to the computer memory. The memory then routes it to the processor and video card. If the user manipulates the photograph, he is changing the data currently stored in the memory. When he is satisfied with his work and decides to save the file under a new name, the memory then transmits the updated picture to the hard drive for permanent storage.
When many people use the word "memory" in reference to computers, they mean the hard drive. Hard drives store data permanently, but the drives are not considered to be memory in the technical meaning of the word. The term memory refers to temporary data storage units. However, hard drives can set aside sectors to act as "virtual memory," an area on the hard drive that acts as temporary, supplemental storage that helps the computer to do more at once without requiring the user to purchase and install more of it.
Other types of computer memory include the cache located on the processor, a high-performance but low size type of memory that stores important information that the processor may need quickly without needing to wait for other, slower memory types to cycle around. Video memory, located on video cards, assists the card in storing and transferring graphical data for processing.