Different Types Of Memory Aqa

Types of Memory

What are the different types of memory within a computer?

• A computer system contains four main types of memory, they are:

  • RAM

  • ROM

  • Cache

  • Register

• RAM and ROM are ‘main memory‘, directly accessible by the CPU

• Registers are covered in more detail here

What is cache?

• Cache is very small, very fast memory located in the CPU which is used to provide quick access to frequently used instructions and data

• The more cache there is, the more data can be stored, which speeds up the performance of the CPU

• It prevents the CPU from having to repeatedly fetch frequently used instructions from RAM

Quick comparison

What is the difference between main memory & secondary storage?

• Computer systems need both main memory and secondary storage to operate

• Both play a crucial role in the operation of a computer system

• A quick comparison of main memory and secondary storage shows:

Why do you need main memory?

• A computer needs main memory because access times are considerably faster than secondary storage

• This means the time taken to complete operations such as the Fetch-Execute Cycle is dramatically reduced 

• Performance of main memory means a much higher cost which limits the amount that is used

• For example, RAM is commonly purchased in 16 or 32 gigabytes whereas secondary storage such as a hard drive is in terabytes