Dual core processors have two separate cores on the same physical machine. This means they can do two tasks at the same time without interfering one with the other or using up the others memory or processing speed. These can be located on the same mother board or separate mother boards. These types of processors are used when several different tasks or operations need to be done simultaneously.

This type of processor acts like a set of twins; they are exactly alike but work separately. It is like having two computers in one. Since the dual core processors has two of each, two memories, two information caches and even two front bus connections they can work in different tasks at the same time doubling the speed and capability of the computer.
Dual core processors are not for everyone to have at home or work. This would be a complete waste of equipment and money. They are super fast and designed to perform long and complicated operations at the same time without losing power or speed. The ability to multi-task means they are capable of doing so, and can also be combined into one operation once each processor has finished its part of the work.
Of course they are not made for this; they are made to do two different and completely unrelated tasks at the same time at great speed. You can’t run simple everyday programs on these dual core processors, the operations system must have special applications so both processors can run independently and at the same time use the same mother board and memory caches.
Dual core processors use something called multithread technology to function properly and efficiently. What this multithread technology does is allow you to have three or four completely different programs running on your computer at the same time efficiently and with the same speed they would run they were alone.
Dual core processors are now being used in desktop computers at homes and offices. This technology has evolved and developed very fast because of its great potential in work stations and in a lesser degree in homes. There is nothing special you need to learn to use it. If you can use a desktop computer you will be able to use this technology at a basic level. All that will happen is that you will be able to do many things at the same time on your computer faster and without interruption.

source:http://www.dualcoreprocessor.net/