As CPU makers hit limits in how fast a CPU could run they had to find another way. So we now have more CPUs or cores.
No more space, no more speed but the ability to do more in the same time as one CPU does this and another CPU does something else.
There are long articles and even Computer Science classes if you need more than this.
what is the difference in a core and a duel core, does one have more space or more speed? what are each one good for?