A dual-core or multi-core processor works by combining two physical cores into a central processing unit, allowing the CPU to handle multiple threads of data at once. The core of a CPU is the part that does all of the actual work. In a sense, a dual-core processor is like having two single core CPUs in the same computer; however, since they are directly connected to each other, they can work even more efficiently together.
For a dual-core processor to work, software needs to know how to send threads of information to both cores for processing. Certain applications are much more efficient with multi-core processors than others. Similarly, the computer's hardware and operating software need to be compatible with a dual-core processor.
Even if a certain application does not make significant use of the additional core(s), a computer with a multi-core processor still runs faster because it can process threads from multiple applications at once.
Although a dual-core CPU has twice the processing power as a single-core CPU, it typically does not perform twice as fast. In practice, dual-core processors achieve around a 50-percent performance boost over similar single-core processors. Nonetheless, nearly all operations achieve at least some benefit from a dual-core processor.