We all know that computers have fans in them, but not everyone understands why they’re some of the most important components in your PC. In the following article, we will not only explain why most computers need at least one fan in order to operate effectively, but also how to replace broken or damaged fans, clean your PC correctly, and the importance of simple maintenance.
First off, fans are required in PCs in order to keep the components cool. It may seem obvious to some, but a by-product of most energy transfer is heat, and that is the same for electrical energy. As each device draws power, it creates heat as a by-product. This has to be cooled somehow, so manufacturers install cooling fins, or “heatsinks” to draw the heat out of the electronic component, into the air of the PC case.
In order to ensure efficiency of these heatsinks, we need to make sure our case ambient temperature is as low as possible. This is where fans come in. Your run-of-the-mill OEM PC (DELL, HP etc) will typically come with one fan, and in some cases two. This is usually because the inner components don’t draw enough power (don’t require the power draw of high-performance PC’s), so they are generally fairly cool under workloads.
As power draw in the PC goes up, so too does heat and the importance of adequate case cooling. If you are building or have built a gaming PC, it would be wise to include at least two fans as an absolute minimum. Many people find four fans to be a good amount for your average gaming PC, and the very high end users (people with two or more graphics cards) generally swear by five to six fans to cycle their case air.
So now that we know why fans are important, how do we choose between the hundreds available on the market? While some people will justify spending $30 on a single fan as a good investment, your average user simply doesn’t need to spend this much to ventilate their PC. Thermaltake has a couple of multi-purpose fans today that can be used for nearly any application in cooling your PC. They are quiet enough to use as a case fan, and come with a speed controller to suit them to high-performance use such as CPU cooling if required.
Generally when buying a fan, the general rule of thumb is the cheaper they are, the noisier their motor and bearings will be. Expensive fans will generally be quieter, though you also need to check a fan’s minimum and maximum RPM (revolutions per minute). This number is the most important on any fan, as not only does it give a ballpark figure of how much air can be moved by the fan, it also gives an estimate of the noise produced. You see, it is impossible to make a silent fan over a certain RPM (usually around 1500), even if the motor and bearings are completely silent. Eventually what you hear is the actual air flow. To cut that back, engineers create special fans (like the fans mostly used today) though they are generally more expensive than generic, and still aren’t perfect.
If you are just cooling your case with a single fan, you will likely want something ranging from 1200-1600RPM to keep your case ventilated, though this will raise noticeable noise. For cases with two fans, 900-1200RPM is ideal. If you can’t find fans that specifically run in that small an RPM range, either buy fans that have speed controls, or buy a fan resistor to reduce voltage (and therefore speed) of the fan. Anyone using more than two fans will likely know what they need, and opt for high RPM or low, depending on how they want to balance performance and noise. This could mean anywhere from 600RPM for silent users, all the way to 1800RPM for performance use. Any higher and the PC will be audible from across the room.
As for mounting case fans, it is really rather simple. You simply secure the four corners of the fans to the PC case ventilation grills (usually80mm, 120mm or 140mm in diameter)with screws provided. Occasionally manufacturers include rubber pins instead of screws, which are a little harder to secure but rather self explanatory in their replacement of the screw. It should only take a minute or two at most to secure the fan to the case, with the only thing to remember afterwards is to plug the fan into power.
Fans can either be powered by 4-pin Molex, or the 3-4pin on-board power. Both have been pictured so we can explain a little better. As mentioned previously, you can also use a resistor to reduce voltage (and RPM) of the fan, but you can also purchase what is known as a fan controller. These are useful, as they allow you to manually alter the RPM of your case fans. They are a little more complicated to set up than simply plugging the fans in, but they can be useful for managing case temperatures in the warmer or cooler months.
Finally, cleaning your case and fans is vitally important. If your inner components are caked in dust, the air passing over them will not draw heat away, thus exposing them to the risk of heat failure. Clean heatsinks are happy heatsinks, and the same can be said for fans. If fans are clogged with dust and grime, the motor can burn out due to over work, or the bearings can seize up with moisture and rust. We recommend a clean-out of your PC every 3-4 months, with a very soft bristle brush. Take care, treat the PC gently and it should be fine, brush too hard and you may damage something inside, so please take your time.
To clean up the dust from the fans and heatsinks, have a vacuum cleaner running next to your case. This will draw dust and dirt particles out of the air, and hopefully keep most of it off your floor. We don’t want to put the vacuum into the case however, as the fast-moving air creates static electricity - something you definitely don’t want around your expensive PC components!
NEXT PAGE: Fan componentry explained...
Fan components 101:
This is a 3-pin fan connector. It is standard across most fans suitable for PC cooling. It gains power typically from the motherboard, though it can also be powered by some special PC power supplies, which aren’t as common these days. If your motherboard does not have enough power connectors for your extra case fans, you can purchase a molex adaptor, converting this plug into the one pictured below.
This is a Molex power plug. It has one “male” end while the other is “female”. This means you can daisy chain fans together and power them off a single cable from your PC power supply. While using this method, you may notice the fans do not all spin up fully. This may indicate a low amperage on your power supply, and you should use separate cables for each fan. These can also be converted back to the 3-pin power cable.
There is often confusion when mounting a fan as to the correct way it should face. The answer is surprisingly simple: often a fan will actually have marking or arrows etched into the plastic depicting the front and back (intake and exhaust) of the fan. For those without a diagram on their fan, the front is usually the exposed side, while the rear (exhaust) contains the “structure” of the fan – the motor, bearings and the like.
The red plug pictured here is the power source for 3-pin fans. The sharp-eyed will note that the red plug actually has four pins – the fourth is a ground pin though, and not all that common on modern fans. For reference, the motherboard connectors aren’t always red, though should usually contain some clues next to them in the text. Fan_AUX, Sys_Fan,Pwr_Fan and anything with “fan” in the wording is a safe bet.
This article was brought to you by Thermaltake.