How RAM Memory Works

RAM memory, or random access memory, is memory your computer uses to temporarily store information that can be retrieved in any order. RAM is used to store the data that your computer's central processing unit (CPU) uses to execute a program or operation. While your CPU can get data from your hard drive, RAM access is a much faster process. On the other hand, information stored on your hard drive will still be available after the computer is turned off, while data in RAM is lost when the computer loses power.

The Anatomy of RAM Memory
RAM is composed of integrated circuits in the form of chips. Each circuit is made of millions of storage locations called cells. Cells are arranged in a grid and are made up of a transistor and a capacitor. The transistor is used to control the cell (turning it on or off) and to read its current state. The capacitor holds an electrical charge that is read as a 1 (charged) or 0 (discharged).

Memory cells by themselves have no value without the ability to read and write them. The memory controller circuitry performs these functions. The memory controller circuitry is responsible for:

• Knowing the location of each cell by storing its address (the intersection of the memory cell's row and column in the grid).
• Knowing the state (1 or 0) of each memory cell.
• Writing information to individual cells by applying or removing the electrical charge.
• Refreshing the information in cells on a regular basis (called the refresh sequence). A refresh sequence is needed because the capacitors are like a leaky fish tank; every time water is put in, it gradually seeps out. For a memory cell to be read as a "1," the capacitor needs to maintain a certain amount electrical charge. The refresh sequence makes sure to keep charged memory cells at the proper level.
• Communicating with the CPU.

Putting It All Together
As your CPU loads a program, code and data are loaded into RAM as a series of 1s and 0s known as binary data. Binary data is the native language that a CPU uses to talk to various parts of the computer.

The CPU sends a request to the memory controller circuitry, which reads the information from the hard drive and transfers it to memory cells. As the computer runs the program, it continually sends read and write requests to the memory controller. The wires that connect the CPU and the memory controller are called a bus. Bus technology determines how fast the CPU and memory controller can communicate.

Every computer has a maximum RAM memory amount, which is determined by the number of RAM chips you can install in your motherboard. If you want additional memory, you can use virtual RAM memory, which takes unused disk space on your hard drive and maps it to work as RAM. It's generally best to avoid doing this, as hard-disk RAM is never as fast as a RAM chip, so your computer's speed and stability may suffer.