The CACHE memory is a smaller, faster memory that store between CPU and main memory. The high speed memory use for the CACHE purpose is very costly that is the reason. It is not used as main memory of the computer.
In other word, we can say that “CACHE memory is a very high speed memory built in the processor and it is used between main memory (RAM) and the processor. The performance of CACHE depends on the following:
a) Speed and size of CACHE memory.
b) The logic used to read data around the memory area read by CPU.
c) The logic used to guess next required data by the processor.
Levels of CACHE
In the standard PC, there are two types of level of CACHE are level1 (L1) and level2 (L2).
The L1 CACHE is also known as internal CACHE or primary CACHE because it is a part of same chip as the micro processor. L1 is divided into two section one for data and second for instruction. The main limitation of the L1 CACHE is its size, as this CACHE is made as a part of processor internal to it.
The L2 CACHE is normally much larger such as 256, 512 or 1024 KB. The purpose of L2 CACHE is to constantly read in slightly larger quantities of data from RAM.