PWM control for DC fans

[FuzzyYellow]

Hey everyone, so I have 2 DC fans on my case that I want to control via software on the motherboard, but my motherboard doesn't support voltage control, only PWM. is there some sort of adapter that will interpret the PWM signal and use it to raise or lower voltage? I want my case fans to be quiet when the PC is idling, but I need the full performance of the fans max RPM when under gaming load or my CPU temps get too high. (it's my Power mac G3 case, Limited airflow.) 

 

 

just hoping there was a simple and easy way to do this. anyone know of something like this?

[W-L]

-SNIP-

 

From my knowledge all motherboards capable of PWM control are also able to switch to DC voltage control within the BIOS, as of an adapter the only one I know is the Phanteks hub that takes in a PWM signal but uses 3 pin outputs.

[FuzzyYellow]

From my knowledge all motherboards capable of PWM control are also able to switch to DC voltage control within the BIOS, as of an adapter the only one I know is the Phanteks hub that takes in a PWM signal but uses 3 pin outputs.

really? even my MSI H81-P33?

[W-L]

really? even my MSI H81-P33?

 

It should have an option in the BIOS you can then set fan curves based on temperature from MSI Command Center.

[FuzzyYellow]

It should have an option in the BIOS you can then set fan curves based on temperature from MSI Command Center.

yes, but i didn't see any option to switch to voltage control. I'll look quick and report back.

[FuzzyYellow]

no options at all. I was really hoping there would be something. so that Phanteks hub you were talking about will adjust the speed of the DC fans based on the PWM signal?

[W-L]

no options at all. I was really hoping there would be something. so that Phanteks hub you were talking about will adjust the speed of the DC fans based on the PWM signal?

 

Hmm that's a bit odd usually DC voltage control is the first option available before PWM.

 

As for the Phantek controller it's this unit which take a 4 pin WM signal in and outputs to 3 pin fans:

http://forums.vr-zone.com/hardware-depot/3167542-phanteks-pwm-fan-controller-hub-review.html

[Deli]

yes, but i didn't see any option to switch to voltage control. I'll look quick and report back.

MSI mobo will switch to PWM or DC depends on the fan. It will do it automatically. Even though all fan headers are 4-pin. The real PWM one will allow you to adjust from 20% - 100% fan speed and the DC fan header can only do 50% - 100%, regardless the type of fan you plug in.

 

For your particular mobo. I'd expect only the CPU-FAN is real PWM. The rest are only DC.

[W-L]

MSI mobo will switch to PWM or DC depends on the fan. It will do it automatically. Even though all fan headers are 4-pin. The real PWM one will allow you to adjust from 20% - 100% fan speed and the DC fan header can only do 50% - 100%, regardless the type of fan you plug in.

 

Ah new thing you learn everyday 

[FuzzyYellow]

MSI mobo will switch to PWM or DC depends on the fan. It will do it automatically. Even though all fan headers are 4-pin. The real PWM one will allow you to adjust from 20% - 100% fan speed and the DC fan header can only do 50% - 100%, regardless the type of fan you plug in.

 

For your particular mobo. I'd expect only the CPU-FAN is real PWM. The rest are only DC.

hmm. well, it still won't change the fan speed...

[Deli]

hmm. well, it still won't change the fan speed...

I don't have the problem with my MSI mobo. Which are Z97M Gaming and Z77a-GD55.

 

Is none of the fan headers working?

[FuzzyYellow]

I don't have the problem with my MSI mobo. Which is Z97M Gaming.

maybe it's because it's a cheapo board?

[Deli]

maybe it's because it's a cheapo board?

I have had two MSI mobo. They both work the same way.

 

However, I have a Asus mobo. Which one of the three fan headers will only do full speed after six months of normal operation. So, the question is, do all fan headers on your mobo not working at all?

[W-L]

maybe it's because it's a cheapo board?

Regardless it should still automatically do 3 pin DC voltage control even on the cheapest of boards out there.

[FuzzyYellow]

I have had two MSI mobo. They both work the same way.

 

However, I have a Asus mobo. Which one of the three fan headers will only do full speed after six months of normal operation. So, the question is, do all fan headers on your mobo not working at all?

 

Regardless it should still automatically do 3 pin DC voltage control even on the cheapest of boards out there.

hmm. it's still running at full speed. all 3 fan headers on the board work, but only 2 are PWM (CPU, CHA_1) CHA_2 is 3 pin, but there are no options whatsoever for the second chassis fan.

[Deli]

hmm. it's still running at full speed. all 3 fan headers on the board work, but only 2 are PWM (CPU, CHA_1) CHA_2 is 3 pin, but there are no options whatsoever for the second chassis fan.

So, the CPU and CHA-1 is working. But the CHA_2 is only doing full speed. Does the BIOS has a option to adjust fan profile for CHA-2?

 

If the BIOS has that option, but the fan isn't responding. Then , the fan header might be broken(like my Asus). The only way to reduce fan speed is to use a low-noise-adaptor, or device like NZXT Grid+ V2.

[FuzzyYellow]

So, the CPU and CHA-1 is working. But the CHA_2 is only doing full speed. Does the BIOS has a option to adjust fan profile for CHA-2?

CHA1 has PWM support, but is still running at full speed. CHA-2 is 3pin only, and full speed.

[W-L]

hmm. it's still running at full speed. all 3 fan headers on the board work, but only 2 are PWM (CPU, CHA_1) CHA_2 is 3 pin, but there are no options whatsoever for the second chassis fan.

 

Oh I see they might have locked that last 3 pin fan as full speed only, some boards still have that as their CPU opt header where you can't control it. 

 

Your best bet is to probably use the Phateks hub if you want to use a bunch of 3 pin fans or to goo over and have all 4 pin PWM fans with splitters.

[Deli]

CHA1 has PWM support, but is still running at full speed. CHA-2 is 3pin only, and full speed.

This is very odd. I've no explanation.

[TheProfosist]

What motherboard do you have that can only do PWM? Normally they can only do voltage.

[FuzzyYellow]

What motherboard do you have that can only do PWM? Normally they can only do voltage.

 

MSI H81M-P33

[TheProfosist]

MSI H81M-P33

You actually seem to be correct. Which is very odd usually only the CPU header is PWM and none of the other are. You system fan 1 is also PWM it seems. system fan 2 has no control at all. Have you tried using non PWM fan on the CPU header and seeing if you can control it?.