CPU performance

A CPU's performance is how quickly it can process instructions. A quicker model gets through the same program in fewer seconds, so a video call connects sooner and a drawing app keeps up with the stylus.

Three common characteristics of a CPU affect its performance. A higher figure for any one of them can make the CPU quicker, but they work together rather than in isolation.

Characteristic	How a specification shows it	Raising it usually means
Clock speed	2.7 GHz	more cycles are carried out every second
Cache size	6 MB	more data and instructions are held close to the CPU
Number of cores	quad-core	more instructions are worked on at the same time

A CPU's specification lists all three together. A laptop advertised as "3.1 GHz octa-core with a 16 MB cache" is quoting each characteristic in turn: 3.1 GHz is the clock speed, octa-core means it has eight cores, and 16 MB is the cache size. Reading the three together is the only way to judge how well that machine will cope with what you want to run on it.

Name each characteristic in full. Write clock speed and number of cores, not just "clock" or "core": on its own, a single word is too vague, because it does not say what is being measured or how many cores there are, and vague answers do not earn marks.

Practise this