| ing fans are normally square shaped and are available | | | | quieter and have a long life span when compared to |
| in a number of sizes. The most common sizes in | | | | those fans with sleeve bearings. These bearings |
| demand include 120mm, 92mm, 80mm and 60mm. | | | | consist of grooves that are spiral in shape. A reservoir |
| Round PC cooling fans are available as well. The | | | | pushes fluid into the groove. Rifle bearing fans can be |
| airflow that is created by these cooling fans is | | | | kept horizontally or vertically. |
| measured in CFM or Cubic Feet per Minute. RPM or | | | | Other bearings include ball bearings, fluid bearings and |
| Revolutions per Minute is the magnitude which | | | | magnetic bearings. |
| measures the speed of the fan’s rotation. Most | | | | Another important component of a PC cooling fan is a |
| users tend to choose fans with a CFM rating which is | | | | fan connector. |
| on the higher side. | | | | These come in different varieties: |
| A majority of PC cooling fans allow users to adjust | | | | The first kind connects the motherboard and the fan. It |
| the RPM so that they are able to modify the amount | | | | is rectangular in shape and is quite wide. This small |
| of noise that is produced. | | | | in-line connector has two tabs which are located |
| Different fans use different bearings. This selection | | | | towards the edge of the component. The pin sockets |
| largely affects the amount of noise that is produced | | | | are spaced far apart and are adequately sized. An |
| as well as the performance of the fan. | | | | example the 3-pin Molex connector. |
| The different types of bearings used include: | | | | The second kind is one which connects the PC cooling |
| 1. Sleeve Bearing: Those fans with sleeve bearings | | | | fan and the power supply. The connector offers a red |
| consist of two surfaces which are covered in grease | | | | and black wire which connects to the power supply |
| or oil. This lubricates the machine and makes friction | | | | and makes sure that the electric current is continuous |
| possible. Fans with sleeve bearings are not considered | | | | and constant. An example is the 4-pin Molex |
| to be ideal because the lubricant tends to get dry | | | | connector. |
| rather quickly which causes the system to fail. If these | | | | The third kind uses the characteristics of the above |
| bearings are kept at a high temperature, it is more | | | | mentioned connectors and consists of two tabs at the |
| likely that the system will break down. They must | | | | centre and another tab which is located towards the |
| always be mounted in a manner which keeps them | | | | side. The spacing and the size is similar to the 3-pin |
| vertical at all times. Even though such PC cooling fans | | | | and the 4-pin. A white wire may also be present which |
| are silent when they are new, they tend to get | | | | adds to the current and makes the fan move faster. |
| extremely noisy over the years. | | | | An example is the Dell Inc. proprietary. |
| 2. Rifle Bearing: Those fans with rifle bearings are | | | | |