PWM vs Non PWM case fan

DukiNuki

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Hey guys can you please explain the difference , google had me confused more than i was before .
Are non PWMs loud because they always run at 100% speed ? can i control them somehow or does the motherboard take care of that according to the system temps ?

 
Non-PWM fans can still have their speed adjusted by the mobo or a dedicated fan controller. PWM fans are more power efficient (although I can't imagine them saving you more than a few watts). I think a given PWM may have a lower minimum speed than an 'equivalent' non-PWM fan, but non-PWM fans can still run slow enough. For the average consumer I can't think of much reason to prefer one over the other.
 
There are three types of system fans.

1) 2-pin fans (rather rare these days). These fans require that input voltage is tweaked in order to control speed. Pretty much all modern motherboards can do this.
2) 3-pin fans. These fans also rely on voltage regulation. The speed control isn't as fine as PWM, but you can control their speed to within 100-200RPM or so. The third wire does not relate to fan speed control, but rather reports fan RPM to the motherboard. It's the two voltage pins that control fan speed.
3) 4-pin fans (PWM). These fans always run at 12V on the first two wires. The third wire reports fan RPM to BIOS while the fourth wire takes care of modulating pulses to the control circuitry attached to the motor. This yields a much finer control than voltage control and allows it to run at very low RPM without the possibility of getting stuck because voltage is too low.
 


This is an airflow optimized fan. It will do well when placed in an open area but will struggle when placed against an obstacle like a heatsink or radiator.

Many people (including my brother) see PWM, don't know what it means and assume they don't need it and that it will be confusing to install so they avoid it.
 

DukiNuki

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Well my case is NZXT 340 ( nothing blocking the front but the dust filter ) , i can get rid of the front filter if it will trouble cooling , i don't care about dust that much . reviews are from people who bought the PWM fans and they have reported some weird noise with it whereas non PWM users said it was so quiet . dont know which one to go for .
 


NZXT designs their cases for superior cooling. Even their finer mesh filters don't hinder airflow enough to worry about it.

As for the two versions of the fans, I've never used them personally so IDK. If you just want to avoid the PWM one bc negative reviews, I can agree with that.
 

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