fan : Computer Hardware Buyers’ Glossary


Modern computers are faster than ever, but they are also hotter. Without cooling fans they would quickly self-destruct. An overheated machine is a flaky machine and a machine that will die an early death. Every 5.0°C (9.0°F) cooler a machine runs doubles its life. Don’t skimp on fans!
Cooling Fans
Where Mandatory? Included? Notes
power supply Built into the power supply. Always included. Make sure its fan is mounted so that it blows air out the back. If it is mounted to suck air into the case, a stray piece of paper could easily block the vents. In modern machines the fan is thermostatically controlled so it is runs only as fast as necessary. This makes a huge difference is how noisy the machine is.
CPU (Central Processing Unit) fan Sometimes included with the CPU. Glued with heat sink compound right to CPU. Blows air down onto the CPU. In modern machines the fan is thermostatically controlled so it is runs more slowly (and more silently) when the CPU is cool.
back case fan Rarely included with the case. Make sure it blows air out the back.
front case fan Rarely included with the case. Make sure it sucks air in the front.
hard drive fan Never included. Needed when you have more than one drive. Mount drives with a spare bay between them for air circulation if possible.
video card fan Always included if required Integrated into the video card.
When installing a fan, make sure you pin any cables out the way of the blades. Fans are more likely to fail than anything else in the computer. Check them every once in a while to make sure they are spinning. If they are noisy, vibrating or emitting a burning smell, turn off the computer and get them replaced immediately. If you run without fully functioning fans, you risk damaging your machine.

Cat hair and dust can clog them. If they fail, sometimes they can be repaired by cleaning. If the power supply fan fails, there is no need to buy a whole new power supply, just get a new fan.

When replacing a fan, take the old one in with you so you will get the exact same size and mountings. Electronic supply stores sell fans at a quarter the price of the usual retail outlets.

If you can’t find a new fan with compatible power connectors, you can cut part of the tail off your old fan and cut off part of the tail of the new fan and wire the old fan’s connector onto the new fan.

Cheap fans last about a year. Better quality fans have smoother bearings, last longer and run quieter.

Modern fans have sensors so that if something blocks them, e.g. An unsecured wire inside the case, they shut down the computer. There is no beep, no flashing lights. Your computer just sits there unable to run to tell you what the problem is.

As you add components, you increase the risk of overheating. The symptoms include:

Normally you just use a bigger (often noisier) fan. The high end solution is a liquid cooling system that runs silently, like a mini-refrigerator to pump heat out of your computer.

Fan Cleaning

Especially if you have carpets, the various fans in your computer will quickly became clogged with dust. This will cause your computer to overheat, shut down mysteriously or even catch fire. The easiest way to clean them is with a blast from a can of compressed air. You can use a toothpick to pry loose bits of compacted dust. Check that fans are spinning properly and silently. Replace any noisy or non-working fans.

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