Motherboards have a limited number of fan headers. Sometimes the number of fan headers is way lower than the amount of CPU fans you have on your case. So, exactly, how to connect extra fans to motherboard?
If you want to add extra fans to your motherboard, you can get a Y splitter that allows for multiple fans to be connected to a single fan header or go for a Fan Hub that requires a separate power supply. Be warned, however, that most headers are limited in terms of how much power they can supply. A fan header typically has a 1 amp rating.
When using a Y splitter two CPU fans is generally okay for a single fan header. Three CPU fans can start to push the limit of the power a single fan header can supply.
It is quite important to check the fans’ amperage since it will be the determining factor on how many fans you can actually run off the motherboard and the splitter.
For instance, you can only run two 0.5A fans while four 0.25A fans wouldn’t be an issue if your fan header is actually rated at 1 Amp.
A workaround for higher amps CPU fans would be to get a PC fan hub that can draw power directly from the power supply unit (PSU) and thereby, lifting the amperage restrictions of the motherboard fan headers.
In the following text we will explore this topic further.
What is a FAN Header?
Quite simply, Fan Headers are terminals found on your motherboard where you plug your many PC cooling fans. They operate and provide monitoring capability for the fans of your PC.
Types of Fan Headers
There are three types of Fan Headers that you can find on the motherboard:
- CPU Fan Header: For connecting the CPU Fan to.
- System Fan Header: For connecting PC/Case Fans (important for the purpose of this article).
- Power Fan Header: Used for monitoring the Fan of the Power Supply Unit. Your PSU needs to have the monitoring cable for this header to work.
The System Fan Header is the ONLY type of header that is ideal for case fans, splitters and PC fan hubs.
Can You Use CPU Fan Header and Power Fan Header for Case Fans?
Yes, you can use the CPU Fan Header by splitting it if you are seriously short on sufficient System Fan Headers.
You can also use the Power Fan Header, but this header does not provide any voltage control. The fans connected to this header will run at full 100% capacity all the time.
3 Pin vs 4 Pin System Fan Headers
Most modern motherboards offer 4 pin system headers.
The difference between a 4 pin and 3 pin system header is that the former supports PWM Case Fans, whereas, as the latter only supports DC Case FANs.
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Determining the Number of Fan Headers Your Motherboard Has
You can find out the number of Fan headers and their type by looking at your motherboard physically or by reading the manual:
The motherboard above only has two System Fan Headers. Therefore, if you have more than 2 case fans that you need to install, then you will certainly need a splitter.
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Knowing the Difference Between DC and PWM Fans
There are two types of PC fans that you can buy:
- DC Fans
- PWM Fans
DC fans have 3 pins. These have inferior speed control. Often low powered CPU fans are DC fans.
PWM (Pulse Width Modulation) fans use 4 pins. They have a better speed control and are great for minimizing noise.
While there is a list of aspects differentiating the two, the important points to remember between DC and PWM fans for the purpose of this article is that former requires 3 pin header, whereas, the latter requires a 4 pin header.
Also Read: What is Front Panel Header?
How to Connect Extra Fans to Motherboard?
There are two main ways to connect extra fans to your motherboard:
- Using a Y Fan Header Splitter
- Using a PC Fan Hub
1. Using a Y Fan Header Splitter
A fan header splitter is the simplest and the cheapest way to connect more fans to your motherboard header. The number of fans that can be connected via a splitter is contingent on the amperage of the fans as well as that of the motherboard header. A motherboard fan header is usually rated at 1 Ampere.
For safety and performance bottleneck reasons, you should NOT reach the 1 Ampere mark when adding up the rating of all of your fans connecting to a single fan header.
So for instance if you have 2 x 0.4A fans connected to a 2-way splitter, you should have no issues. However, if you have 3 x 0.4A fans connected to a single motherboard fan header, then that is NOT ideal. It is in fact a safety concern.
Setting up the Fan Header Splitter
The setup is very straight forward. The splitter’s female end goes into the fan header on the motherboard. The male ends of the splitter are where the case fans get connected to.
Splitter prices vary on the Y splitter configuration (2-way, 3-way, 4-way and so on). Needless to say, the pricing scales with the number of split ends. But generally they are super cheap.
All splitters are designed to connect to both 4 pin PWM and 3 pin DC fans.
Control on Splitters – NOT Individually Controlled
Splitters often have a single speed control only. In other words, the speed on one Master Fan will dictate the speed of the rest of the connected PC fans.
You cannot set the speed of each fan individually. The motherboards sees all the fans connected to the splitter as a single entity.
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2. Using a PC Fan Hub – For a Huge Number of FANs
Another way to connect multiple fans to your motherboard WITHOUT having to worry about power draw issue is to use a PC Fan Hub.
The beauty about PC Fan Hubs is that they are not limited to the 1 Ampere rating of the motherboard fan headers. They draw power DIRECTLY from the Power Supply Unit using the 15 pin SATA power cables.
As such, you can install multiple high powered fans without having to worry about overloading the motherboard fan header.
Setting up the Fan Hub
Setting up the Fan Hub is also quite straight forward. It requires one SATA power connection from the PSU and one 3 or 4 pin connection from the motherboard header to the Fan hub.
The female end of the Fan Hub connects to the motherboard which then branches into several male headers for you to connect Fans to.
A Fan Hub can typically connect upto 10 fans both 3 and 4 pin PWM or DC fans.
The PC Fan Hubs are almost as cheap as the fan splitters we saw above. However, they do require an extra power supply connection. Therefore make sure you have a spare SATA connector.
More expensive offerings come with baked-in RGB controller, which RGB enthusiasts may actually consider.
You can place the Fan Hubs inside the case. Most come with adhesive tape or magnet that can be used to attach these to the case.
Control on Fan Hubs – NOT Individually Controlled
Like the Y fan header splitters we saw above, the fans connected to the Fan Hubs are also NOT individually controlled.
Essentially, one Fan connected to the master header sets the speed for the rest of the fans.
Molex Version of the Fan Hub
In case if you are using old school Power Supply Unit with Molex connectors instead of SATA connector, you can get a Molex Fan Hub:
Fan Hub With Addressable RGB
If you are a fan of RGB and if you have an Addressable RGB header on your motherboard, then you can find a 2-in-1 Fan+ARGB Hub as well.
Addressable RGB basically means that the color of the LED on the fans can be controlled.
Again, you do need to have an Addressable RGB header for this hub to work. Essentially, with this header, you can have upto 6 PC fans connected with the ability to change their color.
The colors cannot be changed individually for each fan, though.
Also Read: What are PCIe Cables Used For?
As far as how to connect extra fans to motherboard goes, there are two basic ways that we covered above.
If this does not suit you, then there is a third way to add fans to your PC but that does not involve your motherboard. Essentially, you can use 3 pin to Molex adapters that can connect directly to the Power Supply Unit bypassing the motherboard.
However, this method gives you no control over the fans and does not provide you with any monitoring capability.
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