Difference between Intel processor P-cores and E-cores

What is the difference between Intel processor P-cores and E-cores ? Why does some processors have both of them and some processors have only one of them ?

The recent Intel processors may generally have 2 types of cores:

• Performance cores - with focus on the more demanding tasks. P-cores provide a high performance.
• Efficiency cores - with focus on the less demanding tasks. E-cores deliver less performance, but consume less power.

Some CPUs have only the performance cores. High-end CPUs usually have both performance and efficiency cores (known as a hybrid architecture), so they can better optimize the workload.

Both performance cores and efficiency cores have base and turbo frequency, so they can provide an appropriate performance according to how intensive is PC being used.