The cache memory is a smaller, faster memory which stores a copy of the data from the most frequently used memory locations. When the processor needs to read or write to location in the main memory, it first checks whether a copy of that data is stored in the cache. If so, the processor immediately reads from or writes to the cache, which is much faster than read and writing from the main memory.

The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage if cache memory is that the CPU doesn’t has to use the motherboard´s system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed is slowed down to the motherboard´s capabilities. The CPU can process the data much faster than the motherboards system bus.

There are there types or level of cache:

  1. L1 / Internal cache
  2. L2  / External cache
  3. L3 / External cache

The Level 1 or L1 is also known as internal cache because it is built wright into the processor. This level of cache has the lowest capacity as compared to other level, but this level is the fasted because it resides inside the processor so there is no need to use the motherboard slow system bus.

The Level 2 or L2 is also known as external cache because it is placed on the motherboard, between the CPU and the RAM. Some of the new processor have L2 cache inside the processor for faster access to it. This has higher storage capacity but it is slow as compared to the L1 cache.

The Level 3 or L3 is placed on the motherboard. It is the same as the Level 2 cache but since processor have L2 built in the processor this is used instead of the L2.

Basically it is better having a slower processor with a higher capacity of cache in each level than a faster processor and low amount of cache.