FLX Vs PWM: Is PWM Fan Better?

FLX fans reduce fan speed and voltage consumption; on the contrary, PWM one controls the fan speed by pulse width modulation using the motherboard. Both are versions of CPU cooling fans and provide the same …

FLX fans reduce fan speed and voltage consumption; on the contrary, PWM one controls the fan speed by pulse width modulation using the motherboard. Both are versions of CPU cooling fans and provide the same cooling but with different features. Also, the pin and the wireline to these fans are separate, and the controlling take other methods.

Well, the major concern arises is which one will be suitable for your CPU? So, the battle of flx vs pwm fans is given below. Let’s find out.


ConcernFLX FansPWM Fans
Speed3-speed settingCustom setting
Average Noise control18 dB21 dB
Pin Connector34
SystemVoltage ControlFan motor control

Difference in Pin Connectors

Pin connectors play an essential role in these fans. FLX fans are connected to the main switch of the fan, and it includes three-pin connectors. These connectors reduce one to maximum two-degree voltage consumption of the cooling fan and the CPU. Also, three-pin connectors offer three different fan settings, and four-pin connectors offer four different locations.

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However, if you want dynamic control over fan and noise, go for PWM because the pursuit of control over the fan motor provides excess variation in voltage control and cooling.

Fan Speed

You have to use the FLX fan buttons to control the voltage per command. We tried the Noctua FLX fan and upgraded it to 900 and 700 rpm settings. Most flx fans start from 300 and go up to 1200 rpm speed. However, FLX does affect the voltage and decreases it to about 6 watts per cycle.

However, the three-pin connectors of FLX fans directly control the voltage, focusing on the fan motor, which slows down per fan cycle. We also tried Noctua PWM settings to keep it fair rather than switching brands. Pulse width modulation fans have four-pin connectors.

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The three-pin connectors work the same as the FLX ones, but the fourth one sends a signal to the fan motor. You will need your motherboard to control the pulse rate of the fan. PWM fans usually have an average speed of 1200 rpm. If you have a new computer, you can try using the PWM fans.

Noise Contrast

Both the fan versions are famous for being the quietest fans. These don’t make much noise and stay below 23 dB radar. When you command your PWM fan to slow down, the motherboard processes the command to the fan motor in square wave frequency. It decreases sound less than audible human hearing capacity.

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If the CPU generates excess heat, the PWM fan turns to work fast, increasing sound. One of the differences between nf-a12x25 flx vs PWM is that PWM has auto noise decrease technology. Most of the PWM fans can control noise to 21 dB.

One of its advantages is that you don’t need to change it manually; instead, your CPU will do the work. Most FLX fans can control up to 18 dB sound from the CPU.

FLX fans include extra anti-vibration silicone pads that reduce the CPU noise and provide cooling. To keep in mind is flx or PWM whatever fan you use; the noise adjustment must do before setting.

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However, FLX fans come with low sound adapters; unlike PWM, these are just standard cooling fans. So they require extra help. Unfortunately, the higher the FLX fan price, the stronger the noise control. However, it makes less sound than generic fans without the adapter—so no need to worry.

Voltage Consumption

FLX fans are standard cooling fans for CPUs, so they do not offer extra options like PWM. But these do an excellent job for less electricity consumption. Between flx and PWM fans,  FLX provides two options for voltage reduction. One is 7V, and another is 9V. It means either you can reduce the 7-watt voltage or go for 9 watts. So, to adjust the speed, you have to reduce your voltage consumption. Also, most flx fans come with in-line voltage reducers now but offer only three-speed settings. If you don’t bother much about speed issues, choosing FLX fans is better.

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On the contrary, if you want better speed control, then PWM is a suitable choice. The fan motor is directly connected to your computer’s motherboard. So whenever you want to change the fan speed, you can change it using motherboard headers in model line resistors.

Also, the traditional ways of controlling speed using voltage are open for PWM. However, PWM fans offer an extra option to control to reduce voltage consumption for energy saving.


Both of these fans perform fantastically and cool down the CPU. However, the performance quality depends on your personal choice. If you have a moderate PC setting and old CPU and want basic cooling FLX should do the job.

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FLX cools down your CPU and ames very low sound. Our computer CPU worked great after using this. However, the PWM was a beast for our new advanced computers. It offered dynamic and custom speed settings with low noise.

Between noctua flx vs PWM, choosing the best one is a tough choice. Price-wise, PWM fans are slightly more expensive than FLX fans.

Frequently Asked Questions (FAQs)

Are PWM Fans Better?

PWM fans are energy-efficient and run a bit faster than FLX fans. The motherboard header control makes it an attractive choice. However, FLX fans do work great, just like a PWM fan. So, we don’t think it makes that much of a difference.

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Is PWM Better Than FLX?

PWM offers a more dynamic speed range than FLX fans. FLX is standard fans, but it does its basic job right. PWM is an upgraded version from FLX fans. However, it is better than the FLX fan, which makes a difference only in speed control.

Are All Noctua Fans PWM?

No, Noctua provides other fans such as DC & FLX. So, all Noctua fans are not PWM.

Which One Is for You?

If you have read this, you are pretty clear between flx Vs PWM. FLX is your standard cooling fan that needs manual voltage reduction to adjust speed settings, and also these are quiet due to extra anti-vibration.

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On the contrary, PWM fans are controlled by motherboards and pulse waves. It controls speed through a fan motor and also offers different speed settings.

Go for the PWM fan if you have a new computer and are a streamer or gamer. But if you just want to get your basic MS Excel work done, then the FLX fan should be OK.

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