RAM or random access memory is a form of memory that can be accessed at a very fast rate. It is used by the central processing unit or CPU to write and read data as it performs its operations. The CPU needs to store some data for short durations of time while instructions are being executed. This is not stored permanently but created and deleted repeatedly. The faster this can be done, the more efficiently the CPU can operate and this increases the speed of the computer. The primary reason for installing RAM is to give the CPU a fast memory that is several times faster than the hard disk. In the absence of RAM, all data would have to be written to and read from the hard drive by the CPU and this would result in a very slow performance.