case fans How do I control the speed of a 3-pin fan?

[DumboDodo]

I've got the Cooler Master H500 case, and it comes with 2 fans which have a shared 3-pin cable. I can control the 4-pin CPU fan (Wraith Stealth) through ASUS' fan monitoring software (Fan Xpert) but I can't seem to control the H500 front intake fans. I can only completely stop them by enabling the Silent Mode. However, I can't control their RPM or RPM curves in anyway. That's because they're 3-pin fans, so they don't support PMW, but is there any way around this? They seem to be running at full speed all the time. Is there any method through which I can control the RPM and RPM curves for the case fans flexibly such that I'd make a balanced preset between the CPU fan and Case fans?

NOTE: For some reason, these case fans are labeled "AIO Pump" in both the BIOS and the Fan Xpert Software. Additionally, the rear outtake fan isn't recognized at all by neither the BIOS nor Fan Expert, yet all 3 case fans are working perfectly well.

[DumboDodo]

UPDATE: I know this is really confusing, but I found out the fan that's recognized by the BIOS & Fan Xpert is the rear outtake fan, which I am in fact able to control its speed. Turns out the 2 that're at the front are the ones that aren't recognized by neither the BIOS nor the Fan Xpert.

[Streetguru]

10 minutes ago, Deathtroya said:

 

You motherboard needs DC fan control, which is typically a high end motherboard thing only I think.

Or you need an old school fan controller, they're like $10 or something for one with 2 channels.

 

Though I don't know how that might affect the RGB LEDs in that case unless that's a separate cable.

[DumboDodo]

Just now, Streetguru said:

You motherboard needs DC fan control, which is typically a high end motherboard thing only I think.

Or you need an old school fan controller, they're like $10 or something for one with 2 channels.

What I want to know is how am I able to control the rear exhaust fan while not being able to control the front 2 fans so that I can do the same thing (whatever it was that I did to my rear fan) to my 2 front fans so that I can control them as well. If I needed that DC controller or fan controller or whatever, I wouldn't have been able to control the front ones just like I couldn't control the back ones, right?

[Streetguru]

9 minutes ago, Deathtroya said:

What I want to know is how am I able to control the rear exhaust fan while not being able to control the front 2 fans so that I can do the same thing (whatever it was that I did to my rear fan) to my 2 front fans so that I can control them as well. If I needed that DC controller or fan controller or whatever, I wouldn't have been able to control the front ones just like I couldn't control the back ones, right?

Is the back fan 3 pin as well? Just switch which motherboard header the 200mm fans are connected to then?

I couldn't find "DC" on that motherboard's page.

[DumboDodo]

5 minutes ago, Streetguru said:

Is the back fan 3 pin as well? Just switch which motherboard header the 200mm fans are connected to then?

I couldn't find "DC" on that motherboard's page.

That's definitely an option. Would be hard in terms of cable management though. Thanks so much for your help!

[WoodenMarker]

How are the front fans connected to the motherboard? Which headers?

Did you use fan tuning and set the headers they're plugged into to dc?

[DumboDodo]

Both fans have 4 shared headers. I connected the 3-pin female header (power) to CHA_FAN 3 or so, and I connected the 4-pin female (RGB) to the 12v RGB header. When I asked the retailer about the 2 other cables, he told me that I most probably don't need them, which I apparently don't. The fans are working fine and their RGB is, too. Their main pins, however, are 3-pin as I mentioned earlier. That means they don't have PWM. Does that mean I can't control their speeds at all? Also, how do I even know if the MB has DC, and if it does, how do I connect the fans to it?

[Alf84]

https://www.amazon.com/dp/B01HQBNXYK/ref=cm_sw_r_wa_apa_i_.GHoDbSKTF95X

[WoodenMarker]

14 hours ago, Deathtroya said:

3-pin as I mentioned earlier. That means they don't have PWM. Does that mean I can't control their speeds at all? Also, how do I even know if the MB has DC, and if it does, how do I connect the fans to it?

PWM and DC are both different ways to powering fans and either can be used for control. PWM pulses 12v instead of lowering the voltage for lower speeds so the rpm range is better since it doesn't encounter the issue of not having enough voltage to start / keep the fan spinning. 

What motherboard are you using?

Fan control options are often listed in the motherboard manual. 

 

Make sure to quote a post or tag a member when replying or else they won't get a notification that you replied to them.

[DumboDodo]

9 minutes ago, WoodenMarker said:

Make sure to quote a post or tag a member when replying or else they won't get a notification that you replied to them.

Understood.

 

9 minutes ago, WoodenMarker said:

What motherboard are you using?

Asus ROG Strix B450-E

I honestly don't even know where to look in the manual to check if it has that DC thing or not, but it does let me control the CPU fan & rear exhaust fan (even though it's only 3-pin like the front ones) through Fan Xpert.

[WoodenMarker]

5 minutes ago, Deathtroya said:

Asus ROG Strix B450-E

I honestly don't even know where to look in the manual to check if it has that DC thing or not, but it does let me control the CPU fan & rear exhaust fan (even though it's only 3-pin like the front ones) through Fan Xpert.

It's only listed for the aio_pump header in the manual but it wouldn't be the first time Asus has incomplete documentation in their manuals. I'm pretty sure the option should be available for every fan header. By default, it should be set to Auto which usually works but the manual option to toggle between pwm and dc is sometimes useful.

[DumboDodo]

Just now, WoodenMarker said:

It's only listed for the aio_pump header in the manual but it wouldn't be the first time Asus has incomplete documentation in their manuals. I'm pretty sure the option should be available for every fan header.

Wait a minute, this is starting to make a lot of sense. The rear exhaust fan is in fact recognized as "AIO Pump" in both the BIOS & Fan Xpert. That means that the CHA_FAN the rear fan in is the one that supports DC while the others don't. Ultimately, that would mean that if I replaced the locations of the Rear fan cable and the front fans cable, the front ones would be tunable, while the back one won't, right? This makes it much better honestly since I don't need to control the speed of the back one anyway. I only want to control the speed of the front ones.

[WoodenMarker]

1 minute ago, Deathtroya said:

Wait a minute, this is starting to make a lot of sense. The rear exhaust fan is in fact recognized as "AIO Pump" in both the BIOS & Fan Xpert. That means that the CHA_FAN the rear fan in is the one that supports DC while the others don't. Ultimately, that would mean that if I replaced the locations of the Rear fan cable and the front fans cable, the front ones would be tunable, while the back one won't, right? This makes it much better honestly since I don't need to control the speed of the back one anyway. I only want to control the speed of the front ones.

That should work.

Are you able to use dc mode on any of the other headers?

[DumboDodo]

I only have 3 fans in the case. CPU fan, Rear Fan, & front fans (They're 2 but they have shared cables so I counted them as one)

The CPU fan is tunable and speed-adjustable. Same goes for the rear fan. The front ones, however, aren't.

[WoodenMarker]

6 minutes ago, Deathtroya said:

I only have 3 fans in the case. CPU fan, Rear Fan, & front fans (They're 2 but they have shared cables so I counted them as one)

The CPU fan is tunable and speed-adjustable. Same goes for the rear fan. The front ones, however, aren't.

Which header are the front fans plugged into? Have you tried setting that header to dc?

[DumboDodo]

1 hour ago, WoodenMarker said:

Which header are the front fans plugged into? Have you tried setting that header to dc?

I'm sorry, but could you please explain to me what DC is? and what's the difference between it and PWM?

[DumboDodo]

1 hour ago, WoodenMarker said:

Which header are the front fans plugged into? Have you tried setting that header to dc?

In the BIOS there are multiple pre-set curves for the CHA_FAN2 (the 2 front panels) and at the top of the chart there are 2 modes, PWM & DC. It was set to PWM. Should I change it to DC? If I do, will I be able to adjust its speed using Fan Xpert?

[WoodenMarker]

2 minutes ago, Deathtroya said:

I'm sorry, but could you please explain to me what DC is? and what's the difference between it and PWM?

DC (direct current) / variable voltage can be used to control fan speed by changing the voltage. For 12v fans, 12v would mean 100% rpm and lowering the voltage would also lower the fan speed. PWM (pulse width modulation) uses 12v pulses instead of lowering the voltage to control fan speed. For lower rpm, the pulses are less frequent. 

From the perspective of using software controls, there's no difference in this case besides setting the header to PWM or DC.

Just now, Deathtroya said:

In the BIOS there are multiple pre-set curves for the CHA_FAN2 (the 2 front panels) and at the top of the chart there are 2 modes, PWM & DC. It was set to PWM. Should I change it to DC? If I do, will I be able to adjust its speed using Fan Xpert?

Yes, setting it to DC would allow you to control 2-4pin fans. PWM only works for 4pin PWM fans. 

[DumboDodo]

1 minute ago, WoodenMarker said:

DC (direct current) / variable voltage can be used to control fan speed by changing the voltage. For 12v fans, 12v would mean 100% rpm and lowering the voltage would also lower the fan speed. PWM (pulse width modulation) uses 12v pulses instead of lowering the voltage to control fan speed. For lower rpm, the pulses are less frequent. 

From the perspective of using software controls, there's no difference in this case besides setting the header to PWM or DC.

Thank you very much for taking the time to explain this to me.

 

2 minutes ago, WoodenMarker said:

Yes, setting it to DC would allow you to control 2-4pin fans. PWM only works for 4pin PWM fans. 

Well, I opened up the BIOS, set the front fans to DC, but I still can't control them using Fan Xpert 4. Might the problem be with the software? Is there any other program you would recommend for controlling fan speeds?

[WoodenMarker]

1 minute ago, Deathtroya said:

Well, I opened up the BIOS, set the front fans to DC, but I still can't control them using Fan Xpert 4. Might the problem be with the software? Is there any other program you would recommend for controlling fan speeds?

Fan Xpert 4 is generally great already. Did you try using the Fan Tuning first? It may take more than one try for the correct rpm range to be detected for the fan control to work. 

[DumboDodo]

19 minutes ago, WoodenMarker said:

Fan Xpert 4 is generally great already. Did you try using the Fan Tuning first? It may take more than one try for the correct rpm range to be detected for the fan control to work. 

Yes, I used Fan Tuning as well. Unfortunately, no use.

[DumboDodo]

28 minutes ago, WoodenMarker said:

Fan Xpert 4 is generally great already. Did you try using the Fan Tuning first? It may take more than one try for the correct rpm range to be detected for the fan control to work. 

Seems like I'll have to replace their cables after all. Thank you so much for your efforts!

[For Science!]

... the AIO_PUMP header is set to 100% all the time unless you enable control for it on the BIOS.