Speed
In recent years, the speed of the CPU has grown many times in comparison to the access speed of the main memory. Care needs to be taken to reduce the number of times main memory is accessed in order to maintain performance. If, for instance, every instruction run in the CPU requires an access to memory, the computer gains nothing for increased CPU speed—a problem referred to as being "memory bound".
It is possible to make extremely fast memory but this is only practical for small amounts of memory for cost, power and signal routing reasons. The solution is to provide a small amount of very fast memory known as a CPU cache which holds recently accessed data. As long as the data that the CPU needs is in the cache, the performance hit is much smaller than it is when the cache has to get the data from the main memory.
Read more about this topic: Harvard Architecture
Famous quotes containing the word speed:
“It was undoubtedly the feeling of exile—that sensation of a void within which never left us, that irrational longing to hark back to the past or else to speed up the march of time, and those keen shafts of memory that stung like fire.”
—Albert Camus (1913–1960)
“There was such speed in her little body,
And such lightness in her footfall,
It is no wonder her brown study
Astonishes us all.”
—John Crowe Ransom (1888–1974)
“No speed of wind or water rushing by
But you have speed far greater.”
—Robert Frost (1874–1963)