CACHE MEMORY

To facilitate an even faster transfer of instructions and data to the processor, computers are designed with cache memory (see Figure 2-5). Cache memory is used by computer designers to increase computer system throughput. Throughput refers to the rate at which work can be performed by a computer system. Like RAM, cache is a high-speed holding area for program instructions and data. However, cache memory uses internal storage technologies, such as SDRAM, that are much faster (and much more expensive) than conventional RAM. With only a fraction of the capacity of RAM, cache memory holds only those instructions and data that are likely to be needed next by the processor. Cache memory is effective because,in a typical session, the same data or instructions are accessed over and over. The processor first checks cache memory for needed data and instructions, thereby reducing the number of accesses to the slower SDRAM