Computer Case Fans
Computer case fans keep your PC components cool, preventing any damage caused by overheating. If you are building a PC or your current fan is broken, there are plenty of fans to choose from to fit your case.
Choosing the right fan
Computer case fans can be used as an air intake, exhaust fan or to cool the power supply. Whereas a CPU fan is mounted on the component itself, a case fan is fixed to the actual case. A good case fan will keep your computer from overheating and will make your system more stable.
Most fans measure between 70mm and 140mm in size. However, larger fans of 230mm are also gaining popularity. Check your PC's documentation for its hardware specification in order to ascertain which size fan will fit your case.
Airflow vs. Noise
A fan has two desirable attributes - high air-flow generation and low-noise. Airflow is measured in cubic feet per metre (abbreviated as CFM) and the speed of the fan is measured in revolutions per minute (RPM). If the RPM is high, then the fan is spinning fast and increasing airflow, but with the side-effect being that the noise from the fan is also high too. However, larger fans get round this problem as their size means they can move a lot of air at low speeds and make little noise.
When you're looking to buy a new fan, check for its RPM and CFM. The noise of a fan is measured by decibel level (DBA), so keep an eye out for that too if low noise is an important requirement for your PC.
Power Draw
Another attribute of a fan is its power draw. This is the amount of power it draws from the power supply to make the fan work. This is measured in Amps (A).
Connections
Case fans usually connect to the motherboard via 3 or 4 pin Molex connectors. This provides the power to the fan to make it spin. Some cases have 4-pin connectors which enable the motherboard to control the speed of the fan. Check to which connector will fit your motherboard before buying.