CPU performance
Not all processors are equal. Some perform better, and are therefore usually more expensive, than others.
Factors affecting the performance of the CPU:
- Clock speed:clock speedThe speed of a computer's CPU, measured in hertz. This indicates the number of fetch-decode-execute cycles that can run per second. indicates how fast a CPU can run. It is measured in hertz, which deals with how many cycles (instructions) the CPU can process in one second. A 3 GHzGigahertz. One billion hertz per second = one gigahertz. This is a measure of frequency and is used to describe bus speeds and CPU clock speeds. CPU performs 3 billion cycles a second.
- Number of cores: A CPU can contain one or more coreA processing unit within a CPU. CPUs can have multiple cores.. It is common for computers to have multiple cores, such as dual core or quad core processors. The more cores a processor has, the more able it is to run multiple programs at the same time.
- Cache:cache memoryA piece of temporary memory. It can refer to a part of the RAM, storage disk, CPU, or an area for storing web pages. memory is a type of very fast memory situated on or very close to the CPU. It is used to temporarily hold instructions and data the CPU is likely to reuse.
Input and output devices
An input device is one that is used to get data into a computer. An output device is one that allows data to leave a computer, most often in a form intelligible to a human user. Some devices, such as touch screens, are hybrid devices and can do both.
Examples of input devices:
| Input device | Advantages | Disadvantages | Characteristics / Typical uses |
| Microphone | Readily available (in smart phones, tablets, PCs etc.). | Sometimes picks up background noise. | Converts analogue sound waves into digital format. Voice recording on a phone. Talking to friends online. |
| Mouse | Allows a user to control a computer using a GUI. | Requires a certain level of dexterity to use. Can be inaccurate when interpreting precise movements (e.g. drawing). | Selecting icons and options from menus on a screen. |
| Graphics digitiser | Can create more accurate digital hand drawings than a mouse. | Relatively expensive. Requires a certain level of expertise to operate. | Graphic designers sketching ideas on a computer. |
| Touch sensitive screen | Both an input and output device. Very easy to use. | Can become dirty over time. Small objects/icons on screen may be hard to touch accurately. Can be even less accurate than a mouse for precise work. | They work very like a mouse. Used on smart phones, tablets, information kiosks etc. |
| Input device | Microphone |
|---|---|
| Advantages | Readily available (in smart phones, tablets, PCs etc.). |
| Disadvantages | Sometimes picks up background noise. |
| Characteristics / Typical uses | Converts analogue sound waves into digital format. Voice recording on a phone. Talking to friends online. |
| Input device | Mouse |
|---|---|
| Advantages | Allows a user to control a computer using a GUI. |
| Disadvantages | Requires a certain level of dexterity to use. Can be inaccurate when interpreting precise movements (e.g. drawing). |
| Characteristics / Typical uses | Selecting icons and options from menus on a screen. |
| Input device | Graphics digitiser |
|---|---|
| Advantages | Can create more accurate digital hand drawings than a mouse. |
| Disadvantages | Relatively expensive. Requires a certain level of expertise to operate. |
| Characteristics / Typical uses | Graphic designers sketching ideas on a computer. |
| Input device | Touch sensitive screen |
|---|---|
| Advantages | Both an input and output device. Very easy to use. |
| Disadvantages | Can become dirty over time. Small objects/icons on screen may be hard to touch accurately. Can be even less accurate than a mouse for precise work. |
| Characteristics / Typical uses | They work very like a mouse. Used on smart phones, tablets, information kiosks etc. |
Examples of output devices:
| Output device | Advantages | Disadvantages | Characteristics / Typical uses |
| Speaker | Allows users to hear music, voices or communications directly from the computer. | Some internal speakers have poor sound quality. | Used to listen to music or video. Visually impaired users rely on speakers to communicate with a computer. |
| Laser printer | Can print large numbers of pages quickly and in high quality. | More expensive than some other types of printer. Cost to replace toner is relatively high. | Used in schools and offices to print large volumes of data. |
| 3D printer | Allows for rapid production of prototypes and the ability to customise the products you are printing. | Still very expensive and their use is limited by size constraints. | Printing car parts, prosthetics and even human organs. |
| Output device | Speaker |
|---|---|
| Advantages | Allows users to hear music, voices or communications directly from the computer. |
| Disadvantages | Some internal speakers have poor sound quality. |
| Characteristics / Typical uses | Used to listen to music or video. Visually impaired users rely on speakers to communicate with a computer. |
| Output device | Laser printer |
|---|---|
| Advantages | Can print large numbers of pages quickly and in high quality. |
| Disadvantages | More expensive than some other types of printer. Cost to replace toner is relatively high. |
| Characteristics / Typical uses | Used in schools and offices to print large volumes of data. |
| Output device | 3D printer |
|---|---|
| Advantages | Allows for rapid production of prototypes and the ability to customise the products you are printing. |
| Disadvantages | Still very expensive and their use is limited by size constraints. |
| Characteristics / Typical uses | Printing car parts, prosthetics and even human organs. |
