SYS Fan Vs CPU Fan – An In-Depth Comparison Illustration

Are you confused about SYS fan vs CPU fan? The main difference is that the SYS fan is located in the computer case to cool down the inner components, whereas the CPU fan is attached to the heatsink and motherboard to control your CPU’s temperature. Both also vary in functionalities.

If you read further, you will know that these two may sound alike, but these are not. So, without further talking, we would like to take you to the main context to know more!

SYS Fan Vs CPU Fan – All The Teas That You Need

First and foremost, let’s look at what these individually mean. And then, we will show you the comparison in detail.

What Is An SYS Fan?

An SYS (system) fan or commonly known as a case or chassis fan, is the one attached to the front or back, sometimes even in the sides of your computer case. This one brings cool air into the case and blows the hot air. It is attached to the case using four screws or snap-in brackets, sometimes with a combination of screws and brackets.

What Is A CPU Fan?

A CPU fan cools down the heatsink of your computer’s CPU. You will find this one attached to the heat sink directly, which attaches to the motherboard. Additionally, some CPU fans can come as a unit, including a built-in heat sink, which connects entirely to the motherboard.

A CPU fan dedicatedly keeps this vital microchip temp cool. So it removes the heat from the heatsink to the outside and keeps the Central Processing Unit undisturbed.

What Is The Difference Between A SYS Fan Vs CPU Fan?

The main difference between a system and a CPU fan is their functionalities and location. A system fan is installed in the PC case to draw out the hot air and draw in the cool air to keep everything at the optimum temperature.

On the other hand, the CPU fan works to draw out the heat created by the Central Processing Unit, and it is attached to the motherboard of the computer.

The work of a CPU fan is related to the heatsink, or sometimes it even comes as a unit combined with the heatsink. But the system ones don’t operate with any specific cores of the PC.

Usually, 1 CPU blower is enough to cool down the cpu temp, whereas people use more than one as the system fan. This is because your motherboard contains multiple headers to connect the system ones; on the other hand, it has only one CPU header.

Another difference is that the SYS fan cannot control the speed, so it will constantly rotate at the same rate. On the contrary, the CPU fan has speed control to spin the speed necessary for the CPU.


So, now, let’s look at the comparison in a more straightforward way:


Comparison Areas System Fan CPU Fan
Location Top, side or back of the PC case Motherboard, attached to the heatsink
Functionality To draw hot air out of the PC and draw cold air inside to balance the temperature To draw hot air out of heatsink
Header Count In The Motherboard Multiple Single
Speed Fixed, always works at the same speed Smartly maintained speed depending on the necessity
Pins 3 pin 4 pin

Is An SYS Fan Essential To A Computer If You Have A CPU Fan?

When your computer’s CPU and other inner components are running at a safe temperature, you can go on without an SYS fan as long as you have the CPU fan installed. However, the temperature doesn’t seem to rise that much unless you do heavy computer chores. In that case, you can carry on without system ventilation.

But if you constantly do heavy work on your computer or a gamer, you need to install a system fan. In that case, your CPU ventilation alone cannot control the heat built up inside. If you do not install system ventilation in such a case, you will face thermal shutdown or even internal component damage.

Can You Use A CPU Fan As A Case Fan?

Yes, but only with proper modifications. As a case or SYS fan come with 3-pin headers, and the CPU ones have 4 pin headers, you need to modify it to use it for system ventilation.

Types Of Computer Fans:

The SYS and CPU fans are what you need on a computer, but there are other types of cooling systems. So now we will look further into the types that you will see on a computer for your clarification:

●      Case:

We have talked about the case or system fans before. So you already know that you will find these fans on the PC case attached to the back, bottom, side, or top of the case. Case fans can be used as intake or exhaust fans- depending on where you set it up.

Standard case fans come in different sizes like 40, 60, 80, 92, 120, 140, 200, and 220 mm in width, along with height.

●      CPU:

CPU fans are attached to the heatsink to cool your PC’s CPU down. Sometimes it comes individually and sometimes as a unit with the heatsink, which you must attach to the motherboard.

●      Power Supply Unit:

The power supply unit supplies power to the entire PC. As a result, this component gets more heated up over time than the other components. However, the PSU comes with a built-in power supply fan to cool down in time. So you won’t have to add any additional power supply fan in the PSU; instead, you can make an upgrade to the PSU if you notice any mismatch in the outcome.

●      Graphics Card:

Modern graphics cards need individual fans for cooling purposes. But don’t worry, this unit already has a dedicated fan built-in to cool it down adequately.

●      Chipset:

This fan works to handle the temperature of your computer’s chipset on the motherboard. However, this is not that essential for regular PC users.

●      Hard Drive:

This one is rare as well, but it exists in the high- performance computers. So if you are wondering, do hard drives even need a fan? The answer is yes; sometimes, they need a dedicated fan.


Let’s Know About More Micro Details!


What Are Headers?

If you have read it till now, you have already seen us talking about three-pin and four-pin headers. But if you don’t know already, you might be asking, what exactly is a header?

So a header is a socket containing 3 or 4-pin that delivers power to the fan. A header can control the speed, read the spinning rate and vary the voltage produced to the fan. There are two types of headers, 3 pin headers or 4-pin headers, depending on the prongs of the attaching wire.

  • 3-pin header:

These headers deliver three different signals, which are: power, ground, and speed. However, here you cannot adjust the speed manually. Instead, if you want to change the speed, you must adjust the DC source or power. Case fans are attached using 3 pin headers.

  • 4 pin header:

A 4 pin header contains one more signal, which is PWM. It directly controls the fan’s speed so that you can get a smart speed control with this pin. Therefore, you will find these headers in the CPU fans.

PWM Fan Vs. DC Fan: Additions That You Need To Know

Alongside the knowledge of system and CPU fans, you must know about an additional knowledge which is the speed strategy. And the speed is mainly dependent on whether your PC fan is a DC or PWM (Pulse width modulation). Usually, SYS fans are DC, and CPU fans are PWM fans.

To explore this further, let’s look into the DC ones. These are used as your SYS or case fans with 3 pins to connect. The 3 pins are a supply pin, a ground pin, and a signal pin. You can only change the speed if you change the input DC voltage supply.

On the other hand, the PWM is usually the CPU fan that connects to the motherboard with 4 pins. The extra pin is a fourth wire that sends signals to the motor. The speed of these ones is less than the DC fans. But these can vary the speed according to the needs of your motherboard.

Further To Explore:

How Is A CPU Header Different From A System Header?

A CPU header is a 4 pin header, whereas the system header is a 3 pin header. In addition, the CPU header has an extra pin for PWM, which helps control the speed of rotation.

Can A PC Run Without A System Fan?

Yes, if you don’t intend to do heavy usage, your PC can run without a system fan. But if you play games or do heavy use on the computer, you must have a proper system fan to control the temperature. Otherwise, you may ruin the inner components of the computer due to overheating.

Can I Plug A System Fan Into A CPU Fan Slot?

Yes, you can. But you have to make some modifications to the BIOS menu. You need to adjust the curves of the temperature sensor fan so that the BIOS can match the right fan with the correct curve.

How Many Case Or System Fans Do I Need?

You need at least two system fans, one to work as the exhaust and the other one as an air intake fan. But one CPU fan is enough to do all the CPU temperature control.

Everything Is Sorted Out!

So now, you have a clear idea over SYS fan vs CPU fan. We have given every single detail priority for your clarity. You need each of these for different purposes, so you can’t decide between them.

But if you specifically want to know which one is more important, we must say the CPU fan. Because you may go without a system one if you have a CPU fan installed, the latter one is a significant component that you require. So make your decisions wisely.

Nathaniel Villa
Nathaniel Villa