An often underlooked PC component is the case fan. Some people think that computer fans, or case fans, are nothing more than accessories that help add to your PC’s aesthetics, but in reality, their function is as important as the GPU or CPU.
In this article, we’ll discuss about the different types of case fans, how to read their specs, and why computer fans can help your PC in more ways than one.
Why Do You Need More Computer Fans?
When your computer is under heavy load, it generates a lot of heat. Certain components such as the GPU (graphics cards) and CPU (central processing unit or processor) will generate more heat than other components, which is why they come with GPU fans and CPU fans respectively.
Within your PC case, proper ventilation is just one piece of the puzzle when it comes to cooling. You need fans to take in cooler air while expelling warm air at the same time. You won’t always have room temperatures within your PC, but what’s important is that the balance between hot air being expelled and cool air being pulled in is maintained.
Having only one case fan installed might not be enough to maintain this balance, especially when the GPU and CPU are working intensively. As a result, these parts may throttle their performance up until both are cooled down to a reasonable level.
This is why you need to have enough intake fans and exhaust fans to keep your PC as cool as possible even under tremendous loads.
How Do Case Fans Work?
GPU fans and CPU fans only have one purpose, and that’s to expel hot air. Heatsinks found within both the GPU and CPU will transfer heat away from the chips, and their respective fans will suck out the warm air from the heatsink.
Both GPU fans and CPU fans are incapable of keeping the entire system unit cool, which is why you rely heavily on case fans.
As the name implies, case fans are attached to the PC case and they are responsible for managing airflow inside your PC. Depending on your PC case, you’ll most likely have at least one intake fan and at least one exhaust fan that comes with the casing. Some cases will have more than one intake fan or one exhaust fan, so you don’t have to worry about adding more fans.
Laptops come with at least one fan, which is just the intake fan. Hot air generated by the CPU or GPU within a laptop goes out through heating vents. You can supplement this singular case fan installed with a laptop cooler.
All case fans installed within a system unit can also be controlled by a third-party fan controller. This allows you to get the most out of your fans with a single push of a button.
How Do You Read Case Fan Specifications?
Most computer fans, if not all, will share the same specifications as case fans. If you’re thinking about replacing your case’s default fans, you might want to pick up a couple of terminologies below:
Airflow and Static Pressure Optimization
Your fan’s performance is determined by two metrics, namely static pressure and airflow. The latter measures the amount of air moved by a fan at any given time and is expressed in CFM or cubic feet per minute.
Higher airflow means it can move great volumes of air, which positively affects cooling performance as a whole. High airflow fans are meant for exhausting or expelling hot air out of the PC case.
But higher airflow doesn’t necessarily mean it’s better for intake as well. Your PC’s radiator will sacrifice airflow speed to make room for higher static pressure to push air through the fan. This is made possible with the fans’ special blade designs and geometries. Static pressure is measured in Pascals (pa) or millimeters of water (mm H2O). Much like airflow, the higher the static pressure, the better it is at pushing air into the system. This is why static pressure fans are used for intake fans.
To sum it up, you want higher airflow rate for exhaust fans and higher static pressure for intake fans.
Fan size is expressed or measured in millimeters, which is the measure of the diameter of the fan blades or the length of the frame. The fan size will affect the amount of air pushed through the fan.
Generally, the amount of air being pushed by a fan is affected by two factors, namely how fast they spin and the blade’s surface area. Larger fans by default can generate more airflow due to greater surface area, but the additional weight that comes with the size might slow down its aerodynamics. This results in greater power consumption. To control power consumption, larger fans will spin slower than smaller fans but the amount of airflow they generate will more or less be the same.
A lot of PC case fans are built to draw in maximum power, regardless of their size, so the total wattage will always be constant.
Long story short, a 200mm fan that has a max RPM of 800 will have the same airflow as a 120mm fan operating at 2000 RPM. Larger fans are also quieter than their smaller counterparts.
Like fan sizing, fan thickness is measured in millimeters and is the second number represented along with the fan size. Fan thickness ranges from 10mm to 40mm.
But for some odd reason, thicker fans will have more airflow compared to a thinner fan of the same size. This is because thicker fans have blades with a steeper angle of attack than a thinner fan would have, allowing them to scoop up more air per spin.
A thicker fan also has greater depth that adds to the surface area, and the thick frame helps improve the fan’s inherent suction, resulting in higher static pressure than a thinner fan.
Voltage-Based Fan Speed Control and PWM
One reason why fans should be attached to motherboards is the microprocessor-based speed control. Compared to DC fans that come with only two wires (one for ground and one for power), PC case fans come with an extra or third wire for the tachometer signal, which relays the fan’s speed using the onboard Hall-effect sensor.
Three-pin case fans will allow the PC to detect the fan speed and control it, resulting in quiet but cooler performance. Fan speed is regulated by modulating voltage. You’d have higher voltage for higher speeds, and in contrast, lower voltage for lower fan speeds. The latter is not ideal as performance is negatively affected.
What Are The Different Case Fan Sizes?
A case fan will have two dimensions, the diameter and the width (thickness). A good example would be 120mm x 25mm thick. This means that the diameter of the case fan is 120mm and the width is 25mm.
Now, let’s talk about the different PC case fans’ sizing:
80mm or 3.1 Inches
80mm fans have been used for more than a decade and are used in CPU heatsinks and some graphics cards. Fans of this size usually have speeds of about 5000 to 7000 RPMs (revolutions per minute).
Because of their size, they need to work harder to draw in the same amount of air as their bigger counterparts. Because of the amount of work they do, these fans are the noisiest out of all the other fan sizes.
80mm fans are used for smaller PC cases like Mini ATX, Mini ITX, and even SSF and HTPC cases.
92mm or 3.6 Inches
Bigger than the 80mm fans, the 92mm fans are considered to be an improvement over their predecessors but with lesser RPMs. However, some users found out that despite their low RPMs, some brands of 92mm are noisier than 80mm fans.
92mm fans are commonly found in heatsinks for graphics cards, however, the same thing can’t be said for their use on cases. PC cases rarely use 92mm fans compared to 80mm fans, for which the latter is widely used.
120mm or 4.7 Inches
The 120mm fan is considered the standard fan size, replacing both the 80mm and 92mm fan models. Unlike its predecessors, 120mm fans are more useful and more flexible since they can be used on Mini ITX cases up to Full Towers.
Most of the high-end cooling fans are about 120mm or bigger, so you should always go for this size if your PC case allows it.
120mm fans are also known for their high airflow and quiet performance, but that depends on the brand or model. Some fan models of this size have low RPMs that result in low noise overall, but there are high RPM models for those who want maximum cooling power.
140mm or 5.5 Inches
Next to the 120mm is the 140mm computer case fan, which is the second most popular choice of sizing for a lot of PC builders but minus the 120mm”s flexiblity. 140mm fans are usually installed in mid-tower PC cases or bigger. Compared to the 120mm fans, 140mm fans have less static pressure but the airflow is relatively higher.
Both the 120mm fans and 140mm fans are similar in terms of airflow, but the latter is the main choice for mid-tower ATX cases, full towers and EATX or Extended ATX towers with liquid cooling radiators.
The downside to using 140mm fans is that they’re more expensive than 120mm fans, but there’s no discrepancy in performance between the two sizes.
180mm or 7 Inches
180mm fans are the rarest of them all because not a lot of brands manufacture them. One reason why most brands avoid this size is their compatibility. 180mm fans can only be used on full tower cases or bigger.
But with their size come higher airflow and lower RPM. Static pressure is lower, so you’ll find that most of the 180mm fans are used for exhaust fans.
200mm or 7.9 Inches
Last but not the least, we have the largest size of them all: the 200mm case fans, which are used for specialized computer cases.
200mm fans have higher airflows at low RPMs, usually averaging 800RPMs. They’re quieter than all of the other fans on here while also having the highest airflow. However, its static pressure is so low that people only use 200mm fans for keeping up positive or negative air flows. If a PC case can’t handle 2 120mm fans, one 200mm fan will be more than enough to keep hot air out.
Do You Really Need a Fan Control Software?
There’s no definite answer to this question. Unless you’re planning on overclocking your GPU and CPU, you might want to make use of a fan control program or software to keep your system cool.
You might also be lucky to come across case fans with built-in fan controllers that allow you to control fan spins or fan speed with a single remote. If your case has an RGB fan, then you might have this fan controller remote with you.
For gaming laptops, fan control is possible through programs such as ArmouryCrate or MSI Afterburner. You can set multiple profiles that include fan speed to help maximize performance for any game.
The Wrap Up
What kind of case fan do you actually need? Well, you’re more likely to use 120mm fans as they’re more commercially available and compatible with a lot of PC cases. You also have the freedom of accommodating more fans of smaller sizes, or fewer fans of bigger sizes. It’s really up to you.