Sys Fan vs CPU Fan | Comparison Between Them

Before getting into the differences, it’s better to know about these two fans if you already don’t know about them. Sys fan is a computer-based fan designed to maintain proper ventilation in the chassis. On the other hand, a CPU fan is meant to keep your CPU cool by drawing hot air out of it. So, it’s clear that both fans are dedicated to the computer system.

In this post, we’ll talk about why they’re different even though they’re computer-based fans including the differences. So, without delaying any more, let’s get into them, shall we?

Differences Between System Fan and CPU Fan

Before getting into the differences in detail, let’s just start by identifying the quick differences between these two fans. Have a look at the following table –

Quick Difference Table

Factor	CPU fan	Sys fan
Operation	Cools only the CPU	Cools the entire chassis ambient
Location	Usually placed on the CPU heatsink	Usually placed in the front, rear, or top of the chassis
Speed	Usually, the motherboard controls it according to the CPU temperature	Can be controlled by the motherboard or can be set to a constant value
Header	Connected to a 3 or 4-pin PWM header	Connected to a 3 or 4-pin PWM header

Explained the Significant Differences Between Sys Fan vs. CPU Fan

The significant differences between a sys fan and a CPU fan lie in their operation and location. 

When it comes to operation, the CPU fan operates to cool down only the CPU, whereas the sys fan operates to cool down the entire inside of the chassis including the motherboard, CPU, GPU, drives, etc. In both cases, the fans dissipate the excessive heat generated by the components.

In terms of location, the CPU fan stays mounted directly on the CPU heatsink or cooling block. This way the CPU fan can easily exhaust the heat from the processor straightforwardly. On the other hand, the sys fan stays inside the chassis and can be mounted in multiple locations including front, back, and top. This way the sys fan can draw the heat from the overall PC internal hardware. 

Both fans connect to the motherboard’s two different fan headers. The CPU fan gets connected to the CPU_FAN header and the sys fan gets connected to the SYS_FAN or CHA_FAN header (header label can vary on the motherboard) with the power pins. Even though both fans also come with the same amperage rating which is 1A, their spinning speed and the control on it are different from each other. While the sys fan can maintain both constant speed and motherboard-instructed speed, the CPU fan mostly depends on the motherboard to maintain its speed.

In short, a sys fan is for cooling the entire computer system and a CPU fan is for cooling just the CPU.

Frequently Asked Questions and Answers – FAQs

What is the SYS_FAN used for?

SYS_FAN is one type of fan header on the motherboard that is designed to power up the chassis fans of your PC.

Is the chassis fan the same as the sys fan?

Yes, the chassis fan and the sys fan both are the same. They both share the same fan header named either SYS_FAN or CHA_FAN.

Can I connect the chassis fan to the CPU_FAN?

Yes, you can connect the chassis fan to the CPU_FAN header by splitting the header with a Y splitter to connect both the chassis fan and CPU fan simultaneously. But the thing is this will change the way how the chassis fan function. 

Conclusion

Now that you read this far, we hope that you understand the overall differences between a CPU fan and a sys fan. Both of them are used to cool computer parts but still, they’re different than each other by specific hardware. Let us know what you think about these fans and if you have any confusion regarding them.