cache memory

• • Cache memory is a type of high-speed RAM built into the processor.
  • Data can be transferred to & from cache more quickly than RAM so cache is used to temporarily hold data & instructions that the processor is likely to reuse -> faster processing as it doesnt have to wait for the data and instructions to be fetched from RAM.
  • more cache = faster it runs
  • cache is more expensive RAM -> very small in size
  • Cache also has a significantly faster read/write speed than RAM, making it much quicker to retrieve instructions from there instead of from memory (RAM)
• • L1 cache has fast transfer rates, small in size -> most frequently used instructions & data
  • L2 cache bigger in capacity, slower in speed -> data and instructions that are needed less frequently.
  • Level 3 cache located outside CPU core -> slowest, much larger (up to 50 mb).
  • When the CPU searches for data, it looks first in level 1 cache, then level 2 and then level 3. If the data has been found, this is called a 'cache hit'. If the data is not found then the CPU searches in RAM instead which takes more time - this is called a 'cache miss'.