3. Number of cores

Now imagine that the clock cannot be sped up any more for technical reasons. How would you improve performance?

A sensible way forward is to use two CPUs at the same time. The job in hand is shared between the two CPUs.

In an ideal world, running two CPUs would give you twice the performance. In real life this is not quite the case because many applications have not been written to take advantage of extra processors.

However, by having more than one processor, you would certainly see an improved performance.

A modern processing device may contain two or even four CPUs. Some chip-making companies call these CPUs 'cores'. So a dual-core device means it contains two CPUs and a quad-core contains four.