How Does a Memory Cache Speed Up Computer Processing?by Contributor
Computer processors constantly request information from computer memory at a very fast rate, but the main memory, usually called random access memory (RAM), is unable to respond to these requests at the same speed. Because of this, the processor has to wait for the main memory to return the information it requests, which forces the processor to work at a speed below its maximum capacity. A memory cache is a small amount of memory used by the computer processor to store information that can be retrieved very quickly, reducing the need for the processor to wait for responses from the main memory.
Design of Cache Memory
Most processors today use multiple levels of memory caching, with some of the fastest levels of memory cache built into the processor itself and some of the slower cache levels residing on the motherboard. Each memory cache level increases in size as it gets further away from the processor. The memory cache structure has an index, a pointer to the index in the main memory, the data stored in the main memory and a flag that indicates if the data is still valid.
Operation of Cache Memory
Since the cache memory is a faster subset of the larger amount of main memory in a computer, the processor checks it first when it is looking for information. If the cache contains the information requested by the processor and the information is valid, the processor will use the results from the cache, which are returned to the processor very quickly, improving the operation of the computer. If the information is not in the cache or the information in the cache is marked as invalid, then a cache miss has occurred, and the processor must access the main memory to gather the information. That information is then written to the cache for future use. If there are multiple layers of memory caching, each cache layer operates in a similar manner. The request for data is passed to the lowest layer, and if it doesn't contain the answer, the request is passed to the next layer, and so on until the data is found or the request is passed to main memory.
The key to improving computer processing speed is to allow information to flow through the processor as fast as possible, and a memory cache works toward that goal by reducing the amount of time the processor spends waiting for information. Cache memory is a critical component of all computers designed today, since it improves the performance of the processor, and some amount of memory cache is usually built into the processor itself. The design of the memory cache is important as well, as it affects the ability of the processor to work at its maximum capacity by minimizing cache misses.