What Does Dual Core Mean?
Dual core is a CPU that has two distinct processors that work simultaneously in the same integrated circuit. This type of processor can function as efficiently as a single processor but can perform operations up to twice as quickly. Because each core has its own cache, the operating system is able to handle most tasks in parallel.
Techopedia Explains Dual Core
IBM introduced dual-core chips in its Power 4 microprocessors in 2000. Dual core CPUs were introduced in 2004. Because of the continual increase in single core clock speeds, CPUs were generating more heat and using more power. Dual cores were introduced to improve performance without generating more heat as dual core systems use about the same amount of energy. Processors with triple and quad cores have since been introduced.
While a dual-core system has twice the processing power of a machine with a single processor, this doesn't mean it will always perform twice as fast. This is because some operating systems and programs are not optimized for multiprocessing.