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 computers 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. For example, Intel's "Turbo Boost Technology" can turn off power to entire cores when they are not being used.
It is important to understand that multiple cores are different than multiple CPUs. While a multi-core computer may contain two processing cores on a single chip, a multiprocessor computer may have two CPUs, each with a single processing core. Since multi-core computing is more energy and cost efficient, multi-core computers have become more popular than multiprocessor computers. However, some high-end machines combine the two technologies and include multiple CPUs, each with multiple cores.