In this article, we will talk about fans and, more specifically, about 3-pin vs 4-pin fans.
As you already know, computers use fans to keep their components cool and avoid overheating, but did you know that there are two different kinds of fans, the 3-pin fans and the 4-pin fans?
So, what are the differences between these two fan types? And which one should you use for your computer?
The quick answer is that 4-pin fans are better than 3-pin fans because they have better fan speed control, are faster, and last longer.
If you want to know why this is the case and also learn everything about PC fans, keep reading because, in this easy-to-follow guide, I am going to talk about the 3-pin fans, the 4-pin fans, their differences, and which one you should get for your PC.
A 3-pin fan is a cooling fan that uses 3-pins to connect to the motherboard fan-headers. The 3-pin fans are older and cheaper than the 4-pin fans and are mostly used as case fans in older builds.
They consist of 3 wires that end at the respective pins, each being responsible for a specific task.
- The first wire is the ground wire (0 volts).
- The second wire is the power wire (12V), and its work is to provide the power the fan needs to function.
- The last one is the tachometer (speed sensor) wire, and its job is to send information from the fan to the motherboard about the fan’s current speed, which is counted in RPM (Revolutions Per Minute).
Related Article: Sys Fan vs CPU Fan: ALL The Differences
How do the 3-Pin fans work?
The 3-pin fans are “voltage-controlled fans”, which means they slow down or speed up according to the voltage they get from the motherboard.
For example, when a 3-pin fan receives 12 volts, it will run at 100%. But, if the motherboard wants to slow it down, it will send a lower voltage, for example, 7 volts. Keep in mind that the fans need a minimum power to function (usually around 6-7 volts), and the BIOS settings won’t let you go below that.
So let’s quickly recap and see how the 3-pin fan works:
When you turn your PC on, the fans start spinning at a certain speed. The speed sensor wire continuously sends the motherboard information about the fan’s speed at that specific time in RPM. After the motherboard decides if the fan should work faster or slower, it will either send more voltage (to make it go faster) or less voltage (to make it go slower). This is pretty much how the 3-pin fans work.
Now that you know how the 3-pin fans work let’s talk about the 4-pin fans.
The 4-pin fan is newer and better than the 3-pin fan. It consists of 4 wires that end at the respective pins, just like the 3-pin fan.
And while the first 3 wires are exactly the same as in the 3-pin fans, the 4th wire is what makes all the difference.
The fourth wire is the “PWM wire” (Pulse Width Modulation). Its job is to control the fan’s speed by sending a signal to the motherboard that will either slow it down or speed it up.
But, unlike the 3-pin fan, the power wire always sends 12 volts to the fan, and the speed is controlled by the PWM chip on the fan. The PWM wire transfers the signal from the motherboard to the fan, turning it on and off (in very fast succession) to make it go faster or slower.
Just like we did with the 3-pin fan, let’s quickly recap how the 4-pin fans work.
When you turn the computer on, the 4-pin fans start spinning; just like with the 3-pin fans, the tachometer (3rd wire) sends information about the fan’s speed to the motherboard. Then the motherboard will decide if the fan should run faster or slower and send a pulse signal through the Pulse Width Modulation wire. When the signal reaches the PWM chip in the fan, it will turn on and off the fan to achieve the desired speed.
Okay, now that you know how the four-pin and the 3 pin fans work, let’s see which one is better.
Related Article: How To Connect Extra Fans To Motherboard
3-Pin vs 4-Pin Fan: Which One Is Better?
I already mentioned that the 4-pin fan is better for a few reasons. In this section, I am going to talk about these reasons in detail, so keep reading.
The biggest advantage of the 4-pin fans is that they are quite faster than the 3-pin fans.
I tested both fan types’ speeds through BIOS, and the results were mind-blowing. When both were running at 100% speed, the 3-pin fan reached around 750 RPM while the 4- pin fan reached 1500 RPM.
But why are 4-pin fans almost two times faster than 3-pin fans?
It all has to do with speed control and noise. Remember when I told you that the 3-pin fans are voltage-controlled fans and need a minimum voltage amount to function?
Well, this minimum voltage will keep the fans working at around 60% of their maximum speed. This means they are really noisy most of the time, and the noise would be unbearable if the maximum speed were 1500 RPM.
On the other hand, because 4-pin fans are PWM controlled, they can work as low as 20% of their top speed (meaning most of the time, they won’t make much noise). This happens because their voltage is always 12V, so they will always be getting the minimum voltage they need to function no matter what.
This is why fan control is so important because it allows for higher fan speeds when needed and lower speeds when not.
I guess by now you understand why 4-pin fans are quieter than 3-pin fans, but let’s recap quickly.
Because 3-pin fans are voltage controlled, they need a minimum amount of voltage to function, so they will be running at a higher minimum speed even when they don’t need to, making them quite noisy.
On the other hand, because 4-pin fans are PWM controlled, they have a lower minimum speed so they can be quite silent.
While all kinds of PC fans are quite durable and last for many years, 4-pin fans have a better life expectancy than 3-pin fans.
And as you can probably imagine, it also has to do with the fan speed control. Because 3-pin fans work at higher minimum speeds, they wear out faster than 4-pin fans.
4) Motherboard Compatibility
There is no better or worse when it comes to motherboard compatibility between 3-pin and 4-pin fans.
This has to do with the specific motherboard model you have and the amount of 3-pin vs 4-pin motherboard headers it has. So before buying a 3-pin or a 4-pin fan, check your motherboard and see what types of headers it has.
At his point, I would like to mention that fans are cross-compatible. This means that the 3-pin fan can work in a 4-pin motherboard header (but, of course, it will not be PWM controlled), and the 4-pin fan can work in a 3-pin motherboard fan header (but it will be voltage controlled).
5) Fan Speed Control
While the fan speed control is the most important factor and is the reason for all the advantages PWM fans have over 3-pin fans, I left it for the end because I wanted first to show you one by one all the benefits and, in the end, explain to you the reason why.
Fan speed control allowed manufacturers to make faster, quieter, and more durable fans, which is quite impressive if you think that such a seemingly “minor” thing as better speed control would lead to such a significant advancement.
3-Pin Vs 4-Pin Fan FAQ
Are 3-pin or 4-pin fans better?
4-pin fans are better than 3-pin fans; they are faster, quieter, and last longer. What makes the 4-pin fans better in so many ways is the PWM (Pulse Width Modulation) fan speed control.
Can a 4-pin fan work on a 3-pin header?
Yes, the 4-pin fans work on a 3-pin header. When plugged into a 3-pin header, they will work, but you will not be able to take advantage of their full potential cause they will be voltage controlled and work like 3-pin fans.
Do 3-pin fans run at full speed?
This entirely depends on your motherboard model. If you have an old motherboard, then yes, the 3-pin fans will run at full speed all the time. But on the contrary, if you have a newer motherboard that supports voltage speed control, then it will control the speed of the 3-pin fan.
Can you use 3 pin fan for the CPU?
While most modern motherboards have 4-pin CPU headers, you can use a 3-pin fan for the CPU, but the only problem is that it won’t be PWM controlled so you won’t have the PWM fan benefits.
Are PWM fans 3 or 4 pin?
PWM fans are 4-pins and not 3-pins. The 4th wire of the 4-pin fans cable is the wire responsible for transferring the PWM signal from the motherboard to the PWM microchip inside the PWM fan. The 3-pin fans don’t have this specific wire, so they are not PWM.
Ok, guys, that’s all you need to know about the 3-pin and the 4-pin fans.
I have analyzed why the 4-pin PWM fans are better than the 3-pin fans and all the geeky stuff you should know.
If you have any other questions or if I missed something, please let me know in the comments section below, and I will be more than happy to help you out.
As always, thank you for reading, and until next time, take care and stay tuned!
Nick Ryley is a computer architect and the owner of The Pc Geekz.
His love for playing games got him interested in computers in the first place. He wanted to be able to build a gaming PC that could run all the latest games at max settings, and this has him pursuing a major in computer architecture!
He started this blog to help people out and answer some of the most common questions about computer building