core : Computer Hardware Buyers’ Glossary
A quad-core CPU (Central Processing Unit) chip has four independent CPU
chips all one one piece of silicon. There are four adders, four multipliers etc. that
can work fully simultaneously. Doubling the number of cores does not double the speed
for the same reason doubling the number of workers does not get the job done in half
the time. Having more cores makes your computer run more smoothly since there is
usually a free core to handle work. Work does not block because some other task is
hogging the CPU. It is like having more bathrooms in a house.