PWM fans worth it?

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Tater1337    0

I have a HAF 912 case that I want to manage airflow better, it currently has two 120mm standard fans and I want to max out the fans in can have(two 200mm and one 140mm, and  120mm)


should I look into PWM fans? motherboard (asus p8z77) can support 3 (plus cpu fan). the idea of fan curves appeals to me for noise. finding them is also another matter

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Kaleopan    0

I would strongly advise you to not use PWM fans as case fans in a HAF 912 unless they are set to the lowers RPM possible all the time, which defeats the purpose of having PWM fans in the first place. Especially in the front.


The reason for this is that the HDD cage in a HAF 912 is orthogonal to the air entry of the front fans which will lead to an unparallel amount of noise and significally weaken the airflow anyway. You can make it better by removing the removable 3.5" HDD cage but the bottom fan will always blow directly against the metal.

For case cooling, more fans are always preferable to stronger fans as it will result in more airflow without additional noise.


Also 2x 120mm fans in the front provide a better airflow than 1x 200mm fan.


So for a maxed out airflow you'd have:

Front: 2x120mm (intake)

Top: 2x120mm (exhaust)

Side: 1x140mm (intake or exhaust, depending on if you want positive or negative pressure in your case. i'd go for exhaust)

Rear: 1x120mm (exhaust)

With 6 fans installed you can run very quiet fans at low speeds and still have sufficient airflow in your case.


If noise is not an issue for you, just go for the strongest turbines you can find and put them in.


Another reason for it is that PWM fans are controlled by temperature, so which temperature sensor are you using?

If you go for the CPU sensor, the PWM controlled case fans will have very little impact on the CPU temperature.

The only sensor i can think of that would benefit from PWM fans are the HDD temp. sensors. However if you have a HDD that runs so hot that it triggers PWM fans to speed up, there is most likely a mechanical failure inside your HDD.

So unless you are running an additional dedicated temperature sensor that measures the air temperature in your case, PWM fans for a case are a waste of money and time to configure.

Edited by Kaleopan

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On 4/9/2017 at 2:31 PM, JC Chua said:

PWM Fans allow more granular control of the Fan Speed depending on the Temperatures. It is highly recommended

 I completely agree, three pins fans are better than two pins fans and four pins PWM fans are better than fans with just three pins, 

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Henry Li    0

Not worth it. I thought pwm could go lower rpm than voltage but thats not true. Thats essentially the only advantage so they are exactly the same. 

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