The multi-core processor is a microprocessor that consists of several main processors that reside on a single chip.
There are also multiprocessor systems, here are several processors installed on the motherboard (mainboard, base board). Unlike multi-processor systems, multi- core processors do not have all the resources in multiple copies, but they are shared, which of course does not provide full performance.
In such a case, a 4-Gigaherz processor would be faster than a 2 x 2 GHz multi-core processor, but usually this is very rare and in standard applications it does not matter. In the case of time-critical or computational software, which is important every millisecond, such as games, a processor-specific optimization is sometimes carried out.