What is “Multi-Core Technology” shown in Smartphone Advertisements and how it works

Multi-core technology refers to CPUs that contain two or more processing cores. These cores operate as separate processors within a single chip. By using multiple cores, processor manufacturers can increase the performance of a CPU without raising the processor clock speed. Since the upper threshold of clock speeds has leveled out during recent years, multi-core processors have become a common means to improve computing performance.
Most modern smartphones have at least two cores, or a dual-core processor. Some high-end machines have four core (quad-core), six core (hexa-core), or eight core (octo-core) processors. While adding more cores does not increase the overall computing performance by a proportional amount (two cores do not equal twice the speed), multi-core processors do provide a substantial performance boost over a single-core CPUs. Additionally, a multi-core processor can run more efficiently than a single processor, since not all cores need to be active unless needed.

It is important to understand that multiple cores are different than multiple CPUs. While a multi-core processor smartphone may contain two processing cores on a single chip, a multiprocessor smartphone may have two CPUs, each with a single processing core. Since multi-core computing is more energy and cost efficient, multi-core smartphones have become more popular