This lesson looks at what makes one CPU faster than another and why. You will learn how clock speed, the number of cores and cache size each affect performance, and what an embedded system is with real examples.
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Clock speed
The clock speed of a CPU is the number of instruction cycles it can carry out each second, measured in hertz.
One gigahertz (GHz) means the CPU clock ticks one thousand million times per second.
Increasing the clock speed generally allows the CPU to process more instructions per second, so the computer runs faster.
There is a practical limit, because a higher clock speed makes the CPU generate more heat, which can cause it to become unreliable or overheat.
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1. Why can increasing the clock speed of a CPU not be continued without limit?
2. A CPU has four cores but a program still runs at the same speed as on one core. What is the most likely reason?
3. How does a larger cache improve CPU performance?
4. Which of the following is the best example of an embedded system?