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How to tell if Motherboard fan connectors are PWM

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August 16, 2013 1:38:55 AM

Title says it all, potentially a stupid question. I just bought a Swiftech H220 and it says to plug the pump and the fans into PWM fan ports. How do i find out if my fan ports are PWM (i don't even know what PWM is). I've looked through the manual and its only saying that the Motherboard has CPU header (4 pins), Optional CPU header (4 pins), 3 system fans (4 pins) and anoth system fan (3 pin).

The Cooler came with a PWM splitter, 1 end plugs into the CPU header and the other plugs into the power supply, but it uses a connector that is not on my PSU (it says SATA and has the L-shaped connector of SATA, but i don't have a SATA port on my PSU, and i didn't think SATA could be used power parts)

So my question is: Is there a way tell/test if the fan headers are PWM before i plug the fans/pump into them?

I have a gigabyte GA-z87x ud3h motherboard.

Thanks

(Sorry for the massive amount of questions i've been asking lately...)

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a b V Motherboard
August 16, 2013 1:43:54 AM

Every 4-pin header has PWM. On your board, connect swiftech cooler to port marked CPU_OPT.
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a c 81 V Motherboard
August 16, 2013 1:45:03 AM

The 4 Pins headers on the mobo are all PWM fan connectors. Whereas the 3 Pin ones are for standard fans.
The fans themselves and the Pump power for the swiftech H220 should be having a 4 pin connector. Those need to be plugged into the CPU Header.
To connect the Sata power thing you'll need a Molex to Sata power converter.... it's pretty cheap and ought to be available at any hardware (PC) dealers place closeby.

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August 16, 2013 1:51:30 AM

Bejusek said:
Every 4-pin header has PWM. On your board, connect swiftech cooler to port marked CPU_OPT.


Wow, that was a fast response, thanks :) 

Another potentially a stupid question:
The CPU_FAN has nothing plugged into it at the moment, so would't i be able to just plug the pump into CPU_FAN instead of CPU_OPT (which will then free CPU_OPT to plug in one of the radiator fans).
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August 16, 2013 1:54:48 AM

alyoshka said:
The 4 Pins headers on the mobo are all PWM fan connectors. Whereas the 3 Pin ones are for standard fans.
The fans themselves and the Pump power for the swiftech H220 should be having a 4 pin connector. Those need to be plugged into the CPU Header.
To connect the Sata power thing you'll need a Molex to Sata power converter.... it's pretty cheap and ought to be available at any hardware (PC) dealers place closeby.



Ah, i need a connector, i didn't think of that ( i swear i'm actually smart.... on paper).
I don't think i'll worry about the PWM splitter until i run out of fan ports on the MoBo. It'll save me a few bucks and the fans won't constantly be running at full speed either, but i will probably get one of them soon as i do plan to add another (maybe 2) fans to the case the get the best airflow possible.
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a b V Motherboard
August 16, 2013 3:05:41 AM

not2smart said:
Bejusek said:
Every 4-pin header has PWM. On your board, connect swiftech cooler to port marked CPU_OPT.


Wow, that was a fast response, thanks :) 

Another potentially a stupid question:
The CPU_FAN has nothing plugged into it at the moment, so would't i be able to just plug the pump into CPU_FAN instead of CPU_OPT (which will then free CPU_OPT to plug in one of the radiator fans).


No. OPT header is specifically designed for pump. I don't know if it is actually any different than standard 4pin fan header. Gigabyte says it's for a pump, so use it for the pump :) 

Connect fans to headers marked *_FAN. It would be optimal however, to connect them using a splitter, because this way they are controlled from one port, which makes them spin at equal speed. If you connect each fan to separate header, make sure to set identical fan profiles for these headers in gigabyte software.

What is PWM?
Standard fan have 3 cables attached. Power, ground, rotation speed report channel.
PWM fan have one additional cable attached. It sends modulated impulses to tell it how fast it should spin.
This way it is possible to control it through some kind of software.

BTW I find it hard to believe that your PSU doesn't have SATA power connectors. All modern PSUs do...
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August 16, 2013 3:27:20 AM

Bejusek said:
not2smart said:
Bejusek said:
Every 4-pin header has PWM. On your board, connect swiftech cooler to port marked CPU_OPT.


Wow, that was a fast response, thanks :) 

Another potentially a stupid question:
The CPU_FAN has nothing plugged into it at the moment, so would't i be able to just plug the pump into CPU_FAN instead of CPU_OPT (which will then free CPU_OPT to plug in one of the radiator fans).


No. OPT header is specifically designed for pump. I don't know if it is actually any different than standard 4pin fan header. Gigabyte says it's for a pump, so use it for the pump :) 

Connect fans to headers marked *_FAN. It would be optimal however, to connect them using a splitter, because this way they are controlled from one port, which makes them spin at equal speed. If you connect each fan to separate header, make sure to set identical fan profiles for these headers in gigabyte software.

What is PWM?
Standard fan have 3 cables attached. Power, ground, rotation speed report channel.
PWM fan have one additional cable attached. It sends modulated impulses to tell it how fast it should spin.
This way it is possible to control it through some kind of software.

BTW I find it hard to believe that your PSU doesn't have SATA power connectors. All modern PSUs do...


Okay, i guess i should use the OPT-FAN port. This is what the back of my PSU looks like:


Until i can get my hands on an adapter is it okay to run the fans off the motherboard headers, or do i need to wait until i can get one?
Thanks
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a b V Motherboard
August 16, 2013 3:42:06 AM

It's ok to run them from motherboard headers.
What make and model PSU is that? I'm sure it has to have SATA connectors :) 
Those vertical ports look like a place where you would normally connect SATA cables.
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August 16, 2013 3:51:36 AM

Bejusek said:
It's ok to run them from motherboard headers.
What make and model PSU is that? I'm sure it has to have SATA connectors :) 
Those vertical ports look like a place where you would normally connect SATA cables.


The Power Supply is an Antec High Current Gamer 'Modular' 750w. It doesn't have any SATA connectors, but i fixed the situation. You got me thinking when you mentioned it should have SATA ports, so i though there might be an adapter that came with it. I found an extra SATA cable for the HDDs and i just plugged it into that.
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August 16, 2013 4:07:40 AM

Bejusek said:
Good. Problem solved.

This review shows SATA connectors in this PSU :) 
http://www.techpowerup.com/reviews/Antec/HCG-750M/3.htm...
Bottom of the page, the one before the last photo: this one.
Actually this PSU is supposed to have 9 of them, somewhere in modular bunches of cables.


Thats the exact cable i used :)  Thanks for the help
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November 3, 2013 5:29:32 PM

Bejusek said:
Every 4-pin header has PWM. On your board, connect swiftech cooler to port marked CPU_OPT.


Is this definitely true? The PWM fan I bought doesn't fit my motherboard which has four pins. The keyed plastic prevents it going in. The stock fan looks like the left one in this photo l which new PWM looks like the right one.

I think I possibly have the same issue as the OP in that my manual does not say what the fan plugs are, they are definitely not standard. Maybe the notch/key can be cut off and then it should fit?

Thanks.
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a b V Motherboard
November 3, 2013 11:39:59 PM

Next time please create new topic instead of replaying in a thread marked as solved.

To answer your question: 4pin fan headers on motherboard are normally keyed as for 3pin fans. This allows you to connect either 4pin or 3pin connector and makes sure you plug it in correct orientation.

In the photo you attached, the standard fan connector is on the right, and it should fit to every (either 3 or 4pin) header.

I find it very strange that you can't connect it to your motherboard. What make and model is it?
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November 4, 2013 12:52:37 AM

Bejusek said:
Next time please create new topic instead of replaying in a thread marked as solved.

To answer your question: 4pin fan headers on motherboard are normally keyed as for 3pin fans. This allows you to connect either 4pin or 3pin connector and makes sure you plug it in correct orientation.

In the photo you attached, the standard fan connector is on the right, and it should fit to every (either 3 or 4pin) header.

I find it very strange that you can't connect it to your motherboard. What make and model is it?


Hi, sorry I thought it was still an open thread :S

My computer is a HP Compaq dc5800. I know the motherboard is BTX (might that change things?) but other than that I really can't find proper info about it. :( 

Here is an image of the fan connector (brown) on my motherboard. Sorry it is a bit blurry but I think you can see that the plastic 'back' part doesn't have a hole for the PWM connector key to slot in and will only fit the other 4 pin version.

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a b V Motherboard
November 4, 2013 4:21:48 AM

Yes, I can see the problem. This crappy custom hp mainboard allows only wide-keyed plugs to be connected. I don't know why they made it this way. Probably to keep you from using aftermarket coolers and force to use their own.

Your solution is to mod the connector and remove the obstructing key. Header pinout should be identical with standard 4pin fan header.
I wonder how good will the automatic PWM work on this mainboard.
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November 4, 2013 5:12:46 AM

Bejusek said:
Yes, I can see the problem. This crappy custom hp mainboard allows only wide-keyed plugs to be connected. I don't know why they made it this way. Probably to keep you from using aftermarket coolers and force to use their own.

Your solution is to mod the connector and remove the obstructing key. Header pinout should be identical with standard 4pin fan header.
I wonder how good will the automatic PWM work on this mainboard.


I know, it's rubbish. :(  And they don't even provide proper information either.

Do you think it's likely not to work well? I don't want to ruin an £11 fan but maybe I should just try the piece of the plastic off, hopefully without removing it from the case.

I've noticed in the past that my fan speeds (on monitor programs) never really change, yet they do get louder when I play games. It makes me confused as to whether my fan plug and stock fans are def PWM. :S

Thanks for your replies.
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a b V Motherboard
November 4, 2013 6:27:33 AM

PWM is hardware controlled by motherboard BIOS. It is possible that no software can read/adjust fan speeds on this motherboard. Fans getting louder during load, mean that the PWM is working. In the BIOS (Computer Setup - Power) there is this mysterious setting Thermal. Manual describes it: 'Fan idle mode—This bar graph controls the minimum permitted fan speed'. You can play with it and see if it has any effect on fans RPMs.

As for the plug, cut the plastic off. This way you won't ruin the plug and it will be possible to connect it to any fan header.
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November 5, 2013 4:58:20 AM

Bejusek said:
PWM is hardware controlled by motherboard BIOS. It is possible that no software can read/adjust fan speeds on this motherboard. Fans getting louder during load, mean that the PWM is working. In the BIOS (Computer Setup - Power) there is this mysterious setting Thermal. Manual describes it: 'Fan idle mode—This bar graph controls the minimum permitted fan speed'. You can play with it and see if it has any effect on fans RPMs.

As for the plug, cut the plastic off. This way you won't ruin the plug and it will be possible to connect it to any fan header.


I found the BIOS setting and the stock fan which I've left in gets noticeably gets faster when I turn up the speed. Does this mean PWM is working? It was on minimum by default.

Ok, I'm a little scared to cut the notch off but I think I'll try it! Thanks.
Ps. There is writing on each plug (2510 and ECI9) and I'm assuming this corresponds to the plug in general and not the wires? (Just because they are in different places on each plug so if it did correspond to the wires it would mean they were wired differently, but I think I'm just being paranoid.
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a c 207 V Motherboard
January 4, 2014 11:54:21 AM

not2smart said:
Bejusek said:
Every 4-pin header has PWM. On your board, connect swiftech cooler to port marked CPU_OPT.


Wow, that was a fast response, thanks :) 



Unfortunately it is not correct .... All 4 pin fan headers are NOT PWM. It has become common practice to use 4 pin headers these days, but Asus for example reports that their 4 pin headers for example are NOT PWM.....I rec'd the same answer as this user did direct from Asus.

https://linustechtips.com/main/topic/32579-4-pin-fan-he...

http://rog.asus.com/forum/showthread.php?33662-3pin-4pi...

Quote:
Chassis fan headers control in DC mode only - and that will control 4 pin fans but not in PWM mode.


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January 29, 2014 8:15:32 PM

JackNaylorPE is right.
Just bought a few Noctua PWM chassis fans on the web, and I was wondering if, in fact, my GA-Z87MX-D3H would be able to handle them.
The MB documentation helps you find the truth: the Pins are named differently. CPU_FAN PIN 4 is named "speed control" while SYS_FAN PIN 4 is named "VCC" ... plus the PIN 2 is named "+12V/speed control" wich is the old way to control speed with voltage, not PWM.
So NO, SYS fans don't have PWM ... but YES, PWM fans can be controled the old way (with voltage) ... so my new noctuas should work in my case (since VCC will tell them to always stay on, while +12V/speed control will tune their speed the old way).
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May 5, 2014 11:12:13 AM

fiduce said:
JackNaylorPE is right.
Just bought a few Noctua PWM chassis fans on the web, and I was wondering if, in fact, my GA-Z87MX-D3H would be able to handle them.
The MB documentation helps you find the truth: the Pins are named differently. CPU_FAN PIN 4 is named "speed control" while SYS_FAN PIN 4 is named "VCC" ... plus the PIN 2 is named "+12V/speed control" wich is the old way to control speed with voltage, not PWM.
So NO, SYS fans don't have PWM ... but YES, PWM fans can be controled the old way (with voltage) ... so my new noctuas should work in my case (since VCC will tell them to always stay on, while +12V/speed control will tune their speed the old way).

I have the same Gigabyte motherboard -- why does the bios have manual PWM settings for the 4-pin system fans if none of them are PWM capable? Very strange.
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May 5, 2014 11:33:09 AM

LowVoltage said:
why does the bios have manual PWM settings for the 4-pin system fans if none of them are PWM capable? Very strange.

What do you call "PWM settings" ?
Speed settings are not always "PWM settings". PWM stands for "pulse width modulation", not for speed modulation. Voltage can modulate speed as well.
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May 5, 2014 11:47:46 AM

fiduce said:
LowVoltage said:
why does the bios have manual PWM settings for the 4-pin system fans if none of them are PWM capable? Very strange.

What do you call "PWM settings" ?
Speed settings are not always "PWM settings". PWM stands for "pulse width modulation", not for speed modulation. Voltage can modulate speed as well.


I know what PWM means. :)  The bios for our Gibabyte motherboard has a setting in the bios for the system fans called Manual: Slope PWM. This contradicts our understanding that the four pin system fans do not support PWM control.
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