5. Central Processing Unit (CPU)

 

a. The CPU

The Central Processing unit is the 'brains' of any computer system. It is responsible for all processing in the system. It takes data entered from input devices or held in the main memory or from backing storage and processes it, following instructions contained in software before passing it on to output devices. The CPU is also responsible for processing the instructions contained in the software programs.

The picture shows part of a CPU.

1. The pins are used to plug the CPU into the 'motherboard'.
2. The motherboard is the main circuit board on which all the main electrical components are placed.
3. The pins are covered in gold to make sure a good electrical contact is made. Gold is a very good electrical conductor.

 

 

b. Problems with Heat

When working, the CPU produces a lot of heat. If it gets too hot, computer systems shut down, so ways have to be found to keep it cool.

Older CPU's could rely on Heat Sinks placed on top of the CPU.

These are made of aluminum - a good heat conductor - and come with vanes.

These vanes increase the surface area and help carry heat away from the CPU.

 

 

With newer faster processors, heat sinks are not good enough by themselves to keep the CPU cool.

Now fans are used with heat sinks to keep the CPU cool.

Even so, new processors still produce a lot of heat. The picture below shows an egg cooking from the heat produced by a modern CPU.

 

 

 

 

 

 

c. The Need For Speed

The speed at which CPU's work, is measured in Gigahertz (GHz) . The larger the number, generally the faster the computer. Some new desktops have CPU's that run at 4.3 GHz, which is extremely fast.

But, the actual speed at which computers operate is often much slower because they can only work at the speed of the slowest part of the system and so CPU's often spend a lot of time waiting for the rest of the computer system to catch up.

As well as getting a fast CPU, the next best thing to make computers go quickly, is to add memory. You can never have too much memory!

 

 

 

What you have to do!

In your Word document or your Brain complete the following exercises.

1. What unit of measurement is used to determine the speed of CPU's?
2. What is the problem that designers have to overcome in creating ever faster CPU's?
3. What is the most effective way of increasing the speed of a computer?

 

 

What you should be able to do!

1. Describe the CPU and what it does.

2. Provide the unit of measurement used to measure the speed of the CPU.

3. Explain one other way of increasing the speed at which a computer system works.

 

Continue to 6. Output Devices