Inside Your Computer, Part 3: CPU

Part three of this series will look at the CPU: The Central Processing Unit.

If the power supply is the lifeblood of a computer, and the motherboard the part that keeps it all together, then the CPU, also called a “processor” or “chip”, is the brains of the operation.

The CPU handles all of the instructions of the computer. It tells all of the other parts where to go and what to do. The CPU is assisted in this task by the chipset (more on this later).

The primary function of the CPU is to execute software instructions. Everything in the computer, hardware and software, is processed in series’ of steps. The lines of code that make up all software tell the CPU what needs to be done and in what order.

There are four basic steps the CPU does(which are explained in greater, and more technical, detail here): retrieve instructions from memory(RAM) or storage(hard drive) and place them into a holding area(cache) to await processing.
After retrieval, the instructions are broken down into their various part and handed off to the parts of the CPU designed to execute those parts.
After decoding what instruction need what done done with them, the CPU will execute those instructions, and send the results to the output area.
Finally, the CPU will assemble all of the executed instructed and sends the result back to the working memory where the operating system works with them.

Modern CPUs do so much processing so quickly that they generate quite a bit of heat. So much heat, in fact, that you could fry an egg on an uncovered CPU(provided the egg was less than an inch square, and could be cooked in the 30 seconds or so before the CPUs casing broke from the heat).

Because CPUs generate so much heat that they would cook themselves to death, two measures have been implemented to keep this from happening: a thermostat, and a heatsink/fan combination.

The thermostat measures the CPUs temperature and will turn off the power if the CPUs temperature reaches a dangerous level.
The heatsink and fan combination are whats used to keep the CPU cool. A heatsink is a block of metal that conducts heat away from the CPU and allows the heat to dissipate in the outside air. Its like your cars radiator.

The fan usually sits on top of the heatsink and pulls air over the fins of the heatsink and blows it away from the CPU and motherboard.

Any questions?