Main Memory

Function

When the computer runs a program it first transfers it from some type of of backing store or Secondary Storage. The program in turn may load data from the same or another form of Secondary Storage.

Quantity

The amount of Main Menory in a computer has a direct influence on the size and nature of programs that the computer may run, as well as the speed at which the overall system operates. Memory is actual physical modules that can be inserted and removed from the computer. Adding more memory can often improve computer performance.

Speed/Types

Generally memory is quite fast, but if there isn't enough memory available for a task the computer will try to use some secondary storage as virtual memory. As secondary storage is generally slower than main memory, computer performance suffers as a result. It is important to note that in modern PCs there are actually several different memory type standards. This means that memory from one PC may not be transferrable into another PC. There are also different production & speed standards. So PC100 is slower than the PC133 type. Choosing the fastest memory type suitable for a PC can improve performance for demanding applications like games. Most ordinary applications might not see any benefit from the extra expenditure, however. The main types of memory to be aware of are:

RAM (Random Access Memory; volatile)
ROM (Read Only Memory; non-volatile)
Cache RAM (very fast; expensive; volatility not an issue)
Virtual Memory (Disk space used as memory; slower; volatility not an issue)

For a summary of memory details click here.
Last updated: 20120120-12:20