Cache Memory

The word cache means to store. Cache memory in computer systems is used to improve system performance.

• The idea of introducing cache is that this extremely fast memory would store data that is frequently accessed. It is also called as CPU memory.
• Cache is similar to RAM, but cache uses static RAM where as main memory(RAM) uses dynamic RAM.
• Caching is very much similar to the way you manage your phone numbers where you have favorite sections(cache) and your main contacts(RAM).

  

There are different levels of caching on a system.

• Level 1 - Primary cache which inside the processor.
• Level 2 - Secondary cache which is in the mother board or near to the processor.

Due to high cost CPU comes with relatively small amount of cache compared with main memory.

The process flow of the processor when asked for a file is shown below.

  

Without cache memory everytime CPU requests for data, it would send request to the main memory which would then be sent to the system bus to the CPU. This is a slow process.

• To achieve the quickest possible response time to the CPU we use cache memory.