What is the difference between DC and PWM fans, and which is better?
Posted by deleted_by_reddit@reddit | buildapc | View on Reddit | 20 comments
I know this is a very google-able question but I am reading a ton of different information and I'm just getting more confused.
The only reason I'm looking into case fans is because the ones that came with my NZXT S40 case are loud as heck and I need something quieter. I know that the fans I have are DC because they only have 3 pins, but my motherboard can support 4-pin fans. I can toggle between DC and PWM mode in the BIOS. Supposedly I can also change the "profile" and "speed" for my case fans, but literally none of the options make a difference. My fans are on full blast as long as my PC is on. My PC has no temp problems to warrant the fans being on like that.
To my understanding, my inability to control literally anything about my fans is because they aren't PWM. If that's true, then why are DC fans sold at all? Clearly PWM is better, right? Who is out there saying "Ew, this fan is only PWM. I'll get a DC fan instead because I love full power fans always and I don't want to have any control over my own PC"? Am I totally wrong about this and there's some other problem that's preventing my fans from behaving rationally?
All I want is quiet fans that will slow down when I don't need them. PLEASE ELI5.
Emerald_Flame@reddit
DC is 3-pin. These can be speed controlled by manipulating the voltage going to them. For example, computer fans are typically 12v, so if you only send 7v to them instead, you get roughly 60% speed. Control for these fans is less common as a built in feature in motherboards, but has been becoming increasingly standard over the past 5 years. Many standalone fan controllers that use knobs or sliders are also controlling things this way.
PWM is 4-pin. They always supply the full 12v, but also send a PWM signal, which basically turns the motor off and on extremely quickly. So to get 60% speed on this, you still send the full 12v, but the motor is only on 60% of the time. PWM fans are typically capable of going to much lower minimum speeds compared to DC, they can typically dip down to 20% or lower. Whereas DC is typically in the 40-60% range for minimums.
SWEETclaretCaKe@reddit
I've learned something today.
Thank you Master Knowledge
tiiMb@reddit
You are golden. Still helps me today 7 years later. Thank you sweet prince.
Riftus@reddit
Thanks!
Panthers_Fly@reddit
So just leave em on Auto?
v0lume4@reddit
Thank you!
Miserable-Battle4891@reddit
helped me 7 years later lol
SirAmicks@reddit
Your answer is going to be the top of google results for people searching for this. Kinda neat. Also, thanks.
v0lume4@reddit
You were right.
Pineapple-Muncher@reddit
You were also right
Karritan@reddit
You are right
Ok-Lab684@reddit
For me, the CPU fan in PWM mode, when comparing both fans at minimum speed, is louder than in DC mode. Can I use DC, or is it not recommended?
pixelvince@reddit
Thanks!!
BigGaggy222@reddit
This excellent post is in fact top of the google searches and helped me out today. Thank you.
Guilty_Ad_3844@reddit
Great feedback, I've learned something today, so thanks!!
Vegetable_Win4066@reddit
An amazing answer thank youn
Honest_Committee2544@reddit
still a great answer that helped me today 6 years later.
thank you.
tiiMb@reddit
You are golden. Still helps me today 7 years later. Thank you sweet prince.
very_slippery_fish@reddit
Fjxf xtauixqqqqqoe
Ok-Lab684@reddit
For me, the CPU fan in PWM mode, when comparing both fans at minimum speed, is louder than in DC mode. Can I use DC, or is it not recommended?