Responsible for cooling the main processing unit in a computer, the computer processing unit (CPU) fan setup usually consists of a heatsink and a fan to blow the air. Most modern computer systems also have sensors that tell the computer to turn the fan on when the sensor detects high temperatures that can cause less than optimal performance from a CPU. When you are cooling a CPU and you want the room quiet, choosing the right CPU fan can make a significant difference in the noise levels produced by the cooling system. When deciding on a new quiet CPU fan for your computer, the most important things to keep in mind are the decibel levels of the fan sound, the pitch of sound produced by the fan and whether the size of the fan will fit in your existing computer.
Manufacturers of CPU fans include labels identifying the sound levels in decibels (dB) that the fan usually produces. You can find the sound levels listed in a table located somewhere on the side or back of the CPU box. Manufacturers also list the sound level specifications for their hardware online. When comparing computer fan sound levels, the higher the decibel level is, the louder the fan will be. A quiet CPU fan will often advertise its decibel level in a conspicuous place on the packaging; an exceptionally quiet CPU fan will produce about 19 decibels of sound when it is running.
When choosing a quiet CPU fan, you must not only consider the loudness of the fan, but also the pitch of the sound. High-pitched fans will often create a more grating sound than fans which output lower-pitch sound. The pitch of fan sound is measured in Hertz (Hz). Hertz indicates the frequency of the sound indicated in cycles per second; the higher the number of Hertz, the higher the pitch. Sometimes, the pitch of a quiet CPU fan can be a matter of personal preference; if you find low-pitched humming more offensive than a high-pitched fan, you may want to opt for a fan with sound in a higher pitch.
In some situations, like in a recording studio, a fan may not be quiet enough. Other options for cooling a computer when you need absolute silence include water cooling systems and large heatsinks. With CPU fans, the less often the fan kicks on, the quieter the room will remain. Using a properly installed, high-quality heatsink can help move heat away from the CPU more efficiently, reducing the CPU temperature faster so the sensor turns the fan on less frequently. Copper, a metal with high thermal conductivity, is the best metal to look for in a heatsink.