3 Pin Vs 4 Pin Fan: Telling the Difference

If you’ve dived into the realms of proper PC cooling, then you definitely have come across quite a number of fans. Apart from the dimensions, there are some other noticeable differences. No, I’m not talking about RGB lighting features. This time I’m trying to focus on the fan connectors.

This article is going to be all about 3 Pin vs. 4 Pin fans. It’s essential to have proper knowledge about the components you install inside your precious PC. Especially with powerful current generation hardware, adequate cooling is a must. In most cases, fans are the only way to go about it.

So, let’s discuss the differences and the key factors that make both three-pin and four-pin fans unique. So, read attentively.

What is a 3 Pin Fan?

3 pin fan

You might have noticed; 3 pin fans have three separate indicators. Each has its own particular purpose. The very first wire is there for power. This is limited to 5/12 volts. The second one is for ground, and the third wire is for the tachnometric signal, otherwise known as the speed sensor.

These fans can function by manually increasing or decreasing the fan speeds by controlling the voltage over the first wire/ power wire.

What is a 4 Pin Fan?

4 pin fan

These fans are a bit different from the 4 Pin ones. You’ll find these fans to be compatible with most modern motherboards. The key difference between 3 pin fans and four-pin fans is the PWM wire.

The fourth wire, or the Pulse Width Modulation wire, is used to control the power supply of the specific load and rotation speed of the impeller. If you’re a modern PC builder, then you’ll find the PWM wire to be very helpful.

The best part about this is that it can adjust the RPM with the help of PWM signals and can provide tachometer feedback at the same time. This means, longer the voltage will be drawn, the more speed you’ll get. It works vice versa.

Stating the Differences

Well, we’ve pretty much cleared the whole thing out with the definitions. However, there are some key differences that you might want to know about. Just look at the side-by-side comparison for a better understanding.

3 Pin Fans 4 Pin Fans
Noise can be an issue with three-pin fans as these don’t change rotation speeds according to temperature needs. The PWM feature in 4 pin fans allows RPM to change accordingly with the temps. It causes way less noise than the three-pin variants.
Three-pin fans lose their longevity due to not being able to automatically change the RPM. They lose their efficiency faster. You can expect a longer life span for four-pin fans. They don’t always run at full power and offer better longevity in general.
Three-pin fans are usually the smaller ones that consume less power. Four pin fans can be of greater dimensions and often tend to consume more power.
The voltage and the RPM don’t get reduced accordingly with the CPU needs. Again, this is due to the lack of the PWM wire. Efficiency is the best bit about four-pin fans as they execute perfectly what the three-pin ones can’t due to the additional PWM feature.

Installation Procedure

Another key difference in these fans can be the difference in the ways to install them. This is pretty simple, and you can get the whole idea with a quick read. So, let’s start!

  • Identification

Here’s something you might find interesting. Some fans out there have four-pin connectors. But only three wires go in the back of the connector. This still will be considered as a 3-pin fan.

A typical four-pin PWM fan connector should have 4 square holes in the front. Similarly, you can expect three wires to go inside the rear.

On the other hand, three-pin fan connectors are smaller in size comparatively. Just as the name suggests, it’ll have three square holes in the front and three wires coming in from the back.

  • 3 Pin Fan Connection

Remember, three-pin fans can be connected to a 4-pin header on the MOBO. The fan should function normally without causing any issues. The guides on the fan connector should line up accurately with the tab on the motherboard header. The guides are usually two in number.

After that, all you’ll need to do is, press it down properly until the connection is complete. Don’t apply too much pressure to avoid damage.

  • 4 Pin Fan Connection

If you don’t really require the PWM function, you can actually connect a 4-pin fan to a 3-pin header on a motherboard. It’ll work just fine. But, if you want the PWM features, you’ll need to connect a 4-pin fan to a 4-pin header accordingly.

The process is pretty much the same. Guide the holes to the pins and press down to establish a proper connection.

Final Words

Be it a simple fan connection or connection a liquid-cooled GPU to the motherboard, it’s pretty common to have questions and doubts in the beginning. If you’ve read the whole thing, you probably have a clear picture of the 3 Pin vs. 4 Pin fan topic.

I even added some additional info to clear up the concept entirely. Hope I could help you guys out. My ultimate goal is to provide optimum support regarding all you need to know about PC hardware. This is a small addition to the whole picture.

Enough said. Farewell for now.

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