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Hardware components of the PC In addition to the computer system main memory, the CPU also utilises a special type of high-speed memory known as cache (pronounced cash). Cache memory is much faster than the main memory and provides a faster connection to the processor than main memory. The CPU works directly with cache and the cache in turn, works with main memory. Essentially, the cache memory acts as a high-speed buffer between the CPU and main memory, swapping data and instructions between them. The CPU’s most recently used data is stored in cache enabling the CPU to make use of the faster cache memory for repetitive tasks. The illustration on the left shows this concept. Cache memory is an important factor in determining the overall performance of a computer. Cache memory comes in one of two forms, either internal or external to the processor. Internal cache is built into the processor itself and external cache usually resides outside the physical construction on the processor. Internal cache, or level-one (L1) cache, is between 32KB and 64KB in size for Pentium III Processors. External cache, or level-two (L2) cache, is between 256KB and 2MB in size. L2 cache is now being integrated inside the processor packaging. This improves overall CPU performance as the cache runs at the same speed as the CPU. Click on the diagram to view an animation of the concept.
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