The memory cache is a high-speed memory available inside the CPU in order to speed up access to data and instructions stored in RAM memory. In this tutorial we will explain how this circuit work in an easy to follow language.

A computer is completely useless if you don’t tell the processor (i.e. the CPU) what to do. This is done thru a program, which is a list of instructions telling the CPU what to do.

The CPU fetches programs from the RAM memory. The problem with the RAM memory is that when its power is cut its contents are lost – this classifies the RAM memory as a “volatile” medium. Thus programs and data must be stored on non-volatile media (i.e. where the contents aren’t lost after your turn your PC off) if you want to have them back after you turn off your PC, like hard disk drives and optical media like CDs and DVDs.

When you double click an icon on Windows to run a program, the program, which is usually stored on the computer’s hard disk drive, is loaded into the RAM memory, and then from the RAM memory the CPU loads the program thru a circuit called memory controller, which is located inside the chipset (north bridge chip) on Intel processors or inside the CPU on AMD processors. On Figure 1 we summarize this (for AMD processors please ignore the chipset drawn).