What does PWM mean in case fans?

[Tweed]

I'm looking at the Noctua NF-F12industrial? What does PWM mean? Are they good fans? They seem loud according to their specs, the industrialPPC-3000 has 43.5 dbA and the industrialPPC-2000 has 29.7 dbA. Should I get this fan instead? https://pcpartpicker.com/product/CzM323/fractal-design-case-fan-fdfanventhf12bk . They will be for intake on the bottom of my case on top of a dust filter.

[TheRandomness]

PWM = Pulse Width Modulation. Basically, they can be controlled better. Also, the industrial fans are supposed to be louder because they aren't necessarily going to be used for PCs therefore they may need to push more air therefore they are louder.

[spartaman64]

 it just means you can directly control how fast they spin in rpm if you plug into a pwm header. and noctua are considered some of the quietest fans

[Kryptyx]

Pulse-width modulation. It basically means the motherboard can control the fan speed. Yes they are good and since it's PWM you can adjust the speed (thus sound) of the fan. I have 2 of the NF-F12 Industrial 2000 on my H110.

[Tweed]

1 minute ago, Kryptyx said:

Pulse-width modulation. It basically means the motherboard can control the fan speed. Yes they are good and since it's PWM you can adjust the speed (thus sound) of the fan. I have 2 of the NF-F12 Industrial 2000 on my H110.

Are they loud?

[Tweed]

2 minutes ago, spartaman64 said:

 it just means you can directly control how fast they spin in rpm if you plug into a pwm header. and noctua are considered some of the quietest fans

What do you mean directly? Through software or physical buttons?

[Kryptyx]

2 minutes ago, Tweed said:

What do you mean directly? Through software or physical buttons?

Through your motherboard's bios.

[spartaman64]

3 minutes ago, Tweed said:

What do you mean directly? Through software or physical buttons?

software usually and by directly i mean you can set the exact RPM the fan spins at. a non pwm fan you can still control the speed with voltage but you can only control by what percent of the fans maximum speed and you dont know how fast it is spinning

[Kryptyx]

3 minutes ago, Tweed said:

Are they loud?

I run mine low so they are very quiet. They are better than the stock fans that came with the H110.

[Naeaes]

Pulse Width Modulation. 

 

Traditionally speaking, you'd slow down an electric motor by giving it less voltage. But in addition to the desired slower speed, that results in less toque too. Which hinders your pressure. So rather than lowering the voltage you Modulate (change according to what is needed) the Width (in terms of time longer/shorter) of the Pulse (the on-period of the full voltage). You turn the fan at full +12VDC voltage for a short time, then let it glide idle at 0VDC for a short time, then again push it at +12VDC and let it glide. On-OFF-ON-OFF. The longer you keep it on, the wider the pulse is and the faster the fan will spin. And vice versa. Obviously this is not just a dumb toggle. There's smart electronics built into the fan itself that time the pulses with the rotation of the fan coils.

 

The noctua iPPC fans aren't intended for consumer use. Not always even for computers per se. They're noisy AF because the operators at huge industrial server farms don't care about noise. THey care about efficiency and reliability and the ability to resist the effects of dust and dirt. 

 

Noctua has normal silent PWM fans for use consumers.

[Sakkura]

11 minutes ago, Tweed said:

Are they loud?

The noise level depends how fast they're running. I have an NF-F12 iPPC-2000 on the Corsair H55 radiator cooling my R9 290, and it's not loud unless it's running over 1500RPM. Which is practically never necessary, I just got the fan to have the extra cooling headroom if and when necessary.

 

When it's running at ~1000 RPM or less, it's practically silent. Most games push it to around 1050-1100 RPM, so the difference is just barely detectable even when I'm listening for it. The most demanding games do push it into a more audible range, but still far from loud. Furmark is what it takes to get loud-ish.

 

Also, compared to the regular consumer NF-F12, which tops out at 1500 RPM, the noise level is identical when they're running the same RPMs. The good thing is PWM lets it run just fine at lower RPMs when necessary, and then it's perfectly quiet.

[Sakkura]

11 minutes ago, Naeaes said:

The noctua iPPC fans aren't intended for consumer use. Not always even for computers per se. They're noisy AF because the operators at huge industrial server farms don't care about noise. THey care about efficiency and reliability and the ability to resist the effects of dust and dirt. 

 

Noctua has normal silent PWM fans for use consumers.

They're not "noisy AF" unless you run them at high RPMs. The point of a PWM fan is to allow a wide spectrum of RPMs, so the fan can be very quiet when you don't need lots of airflow, and then as and when you need to push more air, it can still deliver.

[WoodenMarker]

40 minutes ago, TheRandomness said:

PWM = Pulse Width Modulation. Basically, they can be controlled better. 

40 minutes ago, spartaman64 said:

 it just means you can directly control how fast they spin in rpm if you plug into a pwm header. and noctua are considered some of the quietest fans

39 minutes ago, Kryptyx said:

Pulse-width modulation. It basically means the motherboard can control the fan speed. 

PWM regulates fan speed by pulsing 12v as opposed to DC which does so by lowering the voltage. Both methods allow for fan control and they are just different ways of powering the fan. 

38 minutes ago, Tweed said:

Are they loud?

2000 and 3000rpm fans are loud. iPPC fans aren't worth getting for people who don't need the extra robustness and aren't meant for general use anyway.

22 minutes ago, Sakkura said:

Also, compared to the regular consumer NF-F12, which tops out at 1500 RPM, the noise level is identical when they're running the same RPMs. 

I'll have to get back on this when I get back home but I'm pretty sure they don't sound identical since they use different motors. 

[Sakkura]

2 hours ago, WoodenMarker said:

2000 and 3000rpm fans are loud. iPPC fans aren't worth getting for people who don't need the extra robustness and aren't meant for general use anyway.

 

I'll have to get back on this when I get back home but I'm pretty sure they don't sound identical since they use different motors. 

2000 and 3000 RPM fans are loud... when they run at 2000 or 3000 RPM. They're not loud at lower RPMs.

 

I have a regular NF-F12 on my Noctua NH-U12S, and an NF-F12 iPPC-2000 on my Corsair H55. I can't tell much of a difference in noise, at the same RPMs that is. Both should have noise profiles dominated by airflow turbulence rather than motor noise anyway, at least once they're audible.