First of all cache memory is very fast memory that the 
processor can access much more quickly than main memory or 
RAM. Currently processors can operate at speeds much 
greater than affordable, reliable memory can supply the 
necessary data.Cache memory, is much like other memory, 
except it can operate much faster, and much more expensive.

Cache Memory:-A relatively small section of very fast memory
(often called static RAM) reserved for the temporary 
storage of the data or instructions likely to be needed 
next by the processor.Also improves the speed of CPU.