A dual core processor for a computer is a central processing unit (CPU) that has two separate cores on the same die, each with its own cache. It’s essentially two microprocessors in one. This type of CPU is widely available from many manufacturers. Other types of multi-core processors have also been developed, including quad-core processors with four cores each, hexa-core processors with six, octa-core processors with eight, and many processors with an even greater number of cores.
Dual core processor mounted on the motherboard.
In a single-core or traditional processor, the CPU is fed sequences of instructions that it must order, execute, and then selectively store in its cache for quick retrieval. When out-of-cache data is needed, it is retrieved via the system bus from random access memory (RAM) or storage devices. Accessing this drops performance to the maximum speed that the bus, RAM, or storage device allows, which is much slower than the CPU speed.
This situation is exacerbated when the computer user is multitasking. In this case, the processor must switch between two or more sets of data streams and programs. CPU resources are depleted and performance is degraded.
In a dual core processor, each core handles input data strings simultaneously to improve efficiency. Just as two heads are better than one, so are two hands. When one core is running, the other may be accessing the system bus or running its own code.
To utilize a dual core processor, the operating system must be capable of multi-threading and the software must have simultaneous multi-threading (SMT) technology written into its code. SMT allows parallel multi-threading, where cores receive multi-threaded instructions in parallel. Without SMT, the software will only recognize one core. SMT is also used with multiprocessor systems common to servers.
A dual core processor is different from a multiprocessor system. In the latter, there are two separate CPUs with their own resources. In the first case, resources are shared and cores reside on the same chip. A multiprocessor system is faster than a dual-core system, and a dual-core system is faster than a single-core system, all other things being equal.
An attractive value of dual core processors is that they do not require new motherboards, but can be used in existing boards that have the correct sockets. For the average user, the difference in performance will be more noticeable when multitasking, until more software is aware of SMT. Servers running multiple dual core processors will see a considerable increase in performance.