Most people regard the central processing unit (CPU) as the square-shaped microprocessor that fits into a single socket on a motherboard. However, some chips contain two or four or even more CPUs. Each of these may contain separate processors.
To answer the question in the title, we will start by pressing Ctrl + Shift + Esc to bring up Task Manager. Select the Performance tab.
The image above shows that I have a single socket on my server and that it has two cores. However, if I go to Start and search for and select dxdiag, I see this:
So the Intel i7-4770K chip contains 4 CPUs. Or does it? Well, not according to the Device Manager. It says it has 8!
To explain these variances, we need to understand Logical Processors. These are parallel threads that execute a single instruction. A CPU can handle two or more of these at the same time. Imagine a program that calculates a complex equation (e.g. a spreadsheet operation). It could process each step in a serial fashion, but by sending instructions via different channels (threads), the time taken to finish calculations is cut significantly.
In the case of the i7-4770K I mentioned above, there are four CPUs, each capable of supporting parallel operations. Theoretically, a program could make use of all 8 logical processors, but only if it’s designed to do so.
The extent to which a multiple processor such as the i7-4770K can be put through its paces is entirely up to each program, many of which still settle for a single processor. The ones that do exploit a multiple processor’s capacity are mostly games, graphics, and video apps.