Explain Cache Memory

• Cache memory is placed in between the CPU and the RAM. 
• Cache memory is a fast memory, faster than the RAM. 
• When the CPU needs an instruction or data during processing, it first looks in the cache. 
• If the information is present in the cache, it is called a cache hit, and the data or instruction is retrieved from the cache. 
• If the information is not present in cache, then it is called a cache miss and the information is then retrieved from RAM. 
• The content of cache is decided by the cache controller (a circuit on the motherboard). 
• The most recently accessed information or instructions help the controller to guess the RAM locations that may be accessed next. 
• To get good system performance, the number of hits must far outnumber the misses. The two main factors that affect the performance of cache are its size and level (L1, L2 and L3).
• The CPU registers and the cache memory have been discussed in detail in the previous chapter.