If you connect a 3pin fan to a 4pin (PMW) header

[NeilF]

You need to read chapter 1, part 21 of the manual. It clearly shows what the fan header pin-out is:

* CPUFAN1/CPUFAN2 are PWM .. pin-2 is 12v & pin-4 is speed control (PWM)

* SYSFAN1/SYSFAN2/SYSFAN3 are voltage control .. pin-2 is speed control (variable voltage) and pin-4 is NC (not connected to anything.)​

Can I ask your opinion on what this means then? These are the fan headers on a Gigabyte Z97 Gaming 7 mother board...

CPU_FAN

Pin 1 = GND
Pin 2 = +12V
Pin 3 = Sense
Pin 4 = Speed Control​

CPU_OPT

Pin 1 = GND
Pin 2 = +12V/Speed Control
Pin 3 = Sense
Pin 4 = VCC​

SYS_FAN 1, 2 & 3

Pin 1 = GND
Pin 2 = +12V / Speed Control
Pin 3 = Sense
Pin 4 = VCC​

SYS_FAN 4

Pin 1 = GND
Pin 2 = +12V
Pin 3 = NC​

Which ones are PWM, and which are regular 3 pin headers?

I need TWO PWM headers ideally, but I'm concerned there is only one!

Are SYS_FANs 1->3 actually dual purpose? ie: If you put on a PWM fan great? But if you put on a regular 3 pin fan, then they'll behave accordingly?

*confused*

Spoiler

From the manual... BIOS settings....

CPU Fan Speed Control (CPU_FAN Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the CPU temperature. You can adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under the Fan Speed Percentage item.
Full Speed Allows the fan to run at full speeds.
Fan Speed Percentage: Allows you to control the fan speed. This item is configurable only when CPU Fan Speed Control is set
to Manual. Options are: 0.75 PWM value /oC ~ 2.50 PWM value /oC.

CPU OPT Fan Speed Control (CPU_OPT Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the CPU temperature. You can
adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under the Fan Speed Percentage item.
Full Speed Allows the fan to run at full speeds.
Fan Speed Percentage: Allows you to control the fan speed. This item is configurable only when CPU OPT Fan Speed Control is
set to Manual. Options are: 0.75 PWM value /oC ~ 2.50 PWM value /oC.

1st System Fan Speed Control (SYS_FAN1 Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the system temperature. You can
adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under the Fan Speed Percentage item.
Full Speed Allows the fan to run at full speeds.
Fan Speed Percentage: Allows you to control the fan speed. This item is configurable only when 1st System Fan Speed Control
is set to Manual. Options are: 0.75 PWM value /oC ~ 2.50 PWM value /oC.


2nd System Fan Speed Control (SYS_FAN2 Connector) & 3rd System Fan Speed Control (SYS_FAN3 Connector) samer as SYS_FAN1

 

[doyll]

Spoiler

Can I ask your opinion on what this means then? These are the fan headers on a Gigabyte Z97 Gaming 7 mother board...

CPU_FAN

Pin 1 = GND
Pin 2 = +12V
Pin 3 = Sense
Pin 4 = Speed Control​

CPU_OPT

Pin 1 = GND
Pin 2 = +12V/Speed Control
Pin 3 = Sense
Pin 4 = VCC​

SYS_FAN 1, 2 & 3

Pin 1 = GND
Pin 2 = +12V / Speed Control
Pin 3 = Sense
Pin 4 = VCC​

SYS_FAN 4

Pin 1 = GND
Pin 2 = +12V
Pin 3 = NC​

Which ones are PWM, and which are regular 3 pin headers?

I need TWO PWM headers ideally, but I'm concerned there is only one!

Are SYS_FANs 1->3 actually dual purpose? ie: If you put on a PWM fan great? But if you put on a regular 3 pin fan, then they'll behave accordingly?

*confused*

Spoiler

From the manual... BIOS settings....

CPU Fan Speed Control (CPU_FAN Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the CPU temperature. You can adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under the Fan Speed Percentage item.
Full Speed Allows the fan to run at full speeds.
Fan Speed Percentage: Allows you to control the fan speed. This item is configurable only when CPU Fan Speed Control is set
to Manual. Options are: 0.75 PWM value /oC ~ 2.50 PWM value /oC.

CPU OPT Fan Speed Control (CPU_OPT Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the CPU temperature. You can
adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under the Fan Speed Percentage item.
Full Speed Allows the fan to run at full speeds.
Fan Speed Percentage: Allows you to control the fan speed. This item is configurable only when CPU OPT Fan Speed Control is
set to Manual. Options are: 0.75 PWM value /oC ~ 2.50 PWM value /oC.

1st System Fan Speed Control (SYS_FAN1 Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the system temperature. You can
adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under the Fan Speed Percentage item.
Full Speed Allows the fan to run at full speeds.
Fan Speed Percentage: Allows you to control the fan speed. This item is configurable only when 1st System Fan Speed Control
is set to Manual. Options are: 0.75 PWM value /oC ~ 2.50 PWM value /oC.


2nd System Fan Speed Control (SYS_FAN2 Connector) & 3rd System Fan Speed Control (SYS_FAN3 Connector) samer as SYS_FAN1

CPU_FAN is PWM
CPU_OPT is voltage control,
SYS_FAN1/2/3 are voltage control
SYS_FAN4 has no control or RPM sense

VCC is probably "Virtual Circuit Connection" as in not being used. On transistors it means Voltage Collector-to-Collector or Voltage Common Connector, but not sure what it is supposed to represent on fan pinout.

Do you need 2 different fan speed curve controls or just 2 fans on same PWM control? If 2 fans on same PWM control, use a simple PWM splitter.
http://www.overclockers.co.uk/showproduct.php?prodid=CB-071-AK

That one seems expensive, but is braided.
Make sure only one fan is supplying RPM sense / signal to the motherboard.

Here's a drawing of how they re wired.
http://i14.photobucket.com/albums/a331/doyll/PWM/PWMYsplitterpin-outw-2ndrpm_zpsc12becbb-1.jpg

Here's drawing of PWM splitter with PSU power
http://i14.photobucket.com/albums/a331/doyll/PWM/PWMSplitterwithPSUPower_zpsb169bbca.jpg

 

[NeilF]

I need two PWM headers with seperate control. One for the CPU fans (Noctua D14) and one for a fan hub... It does seem the Gigabyte Z97 series only gives you one!

Oh well, ASUS Z97 A it is then! Basically every fan header on that can be flicked between PWM and DC! I was going for the Gigabyte for the dual BIOS... But fingers crossed I'll not regret it with the ASUS!

 

[doyll]

Mind if I ask why you need separate control on them?

 

[NeilF]

Mind if I ask why you need separate control on them?

PWM fan 1 - My Noctua D14 has two fans which can be connected to one header.
PWM fan 2 - Connected to the PWM fan hub in my Phanteks Enthoos case. You can power/copntrol numerous fans off this one hub, but it is controlled via PWM! eg: I might plug 3 fans in the top of my case, and run them slow 90% of the time, until that hot summer afternoon when CPU temps finally get near 80 degrees...

Note: Obviously the case has a front & rear (3-pin) fans in which will run on their own temp/speed mandate.


As much as like the physical look of the Gigabyte Gaming 7, and the thought of its dual bios, the fan control, and general bios control on the ASUS Z97-A looks simpler and powerful. My last Asus has lasted me 6yrs trouble free... So fingers crossed this new one will!

 

[doyll]

PWM fan 1 - My Noctua D14 has two fans which can be connected to one header.
PWM fan 2 - Connected to the PWM fan hub in my Phanteks Enthoos case. You can power/copntrol numerous fans off this one hub, but it is controlled via PWM! eg: I might plug 3 fans in the top of my case, and run them slow 90% of the time, until that hot summer afternoon when CPU temps finally get near 80 degrees...

Note: Obviously the case has a front & rear (3-pin) fans in which will run on their own temp/speed mandate.

Pretty much as I suspected. I've been running case fans for years now with CPU PWM signal .. Both case and cooler fans. Only time it's not perfect is with high powered video cards .. then I use video card PWM signal for fans supplying it with air. Here is link to basics. More info needed just ask.
http://forums.overclockers.co.uk/showpost.php?p=26079729&postcount=5

Edit:
I haven't done it, but have been told we can use Phanteks PWM controlled fan hub and PWM fans on same header by using only the RPM signal from one or the other to motherboard. Makes sense. PWM signal is not dependent on RPM on most if not all motherboards. The PWM signal is simply a percent of full speed base on CPU temp. RPM sensor is more so we can see what the speed is.

 

[NeilF]

Pretty much as I suspected. I've been running case fans for years now with CPU PWM signal .. Both case and cooler fans. Only time it's not perfect is with high powered video cards .. then I use video card PWM signal for fans supplying it with air. Here is link to basics. More info needed just ask.
http://forums.overclockers.co.uk/showpost.php?p=26079729&postcount=5

Edit:
I haven't done it, but have been told we can use Phanteks PWM controlled fan hub and PWM fans on same header by using only the RPM signal from one or the other to motherboard. Makes sense. PWM signal is not dependent on RPM on most if not all motherboards. The PWM signal is simply a percent of full speed base on CPU temp. RPM sensor is more so we can see what the speed is.

Thanks...

I like to keep things simple & straight forwards. With the ASUS Z97-A:-
CPU-FAN1: Noctua D14 fans
SYS-FAN1: Front case fan
SYS-FAN2: Rear case fan
SYS-FAN3: PWM hub -> controlling any number of other case fans (eg: 3 top mounted ones).

With the Gigabit Gamer board, I could not do that as easily. Plus I believe the software (BIOS/Windows) is simpler/more straight forward in the ASUS too.

So I'll just risk not having a BIOS issue and requiring that DualBios feature. And put up with the slight less flashy looks of the physical board too!

 

[setter]

I need two PWM headers with seperate control. One for the CPU fans (Noctua D14) and one for a fan hub... It does seem the Gigabyte Z97 series only gives you one!

Oh well, ASUS Z97 A it is then! Basically every fan header on that can be flicked between PWM and DC! I was going for the Gigabyte for the dual BIOS... But fingers crossed I'll not regret it with the ASUS!

I wouldnt be so sure on an asus board tbh, mine in sig has all 4 pin headers but only the cpu and cpu opt fan headers are PWM. The opt connector mirrors the cpu fans, even the opt chassis fan headers have very limited speed control.

 

[NeilF]

I wouldnt be so sure on an asus board tbh, mine in sig has all 4 pin headers but only the cpu and cpu opt fan headers are PWM. The opt connector mirrors the cpu fans, even the opt chassis fan headers have very limited speed control.

Looking at your manual, all the fans seem to be controlled by Qfan or not?

It doesn't look as "clever" as the BIOS on the Z97-A where you can (hopefully) configure each fan even down to if it is PWM or DC controlled!

New for the motherboards is Fan Xpert 3 this software can detect and control all of your system fans (both PWM and DC models):-

Fan Xpert 3 puts 4-pin/3-pin CPU and case fan controls in one place. It scans each fan's characteristics and delivers custom settings for each fan based on the dedicated area temperatures detected by hardware thermal sensors. Make sure every fan achieves the best balance of cooling performance and low noise. Fan Xpert 3 supports hardware-level PWM/DC combo mode for both the CPU and case fans. It even can reduce the CPU fan speed to below the default minimum, for extra-quiet and power saving operation during light loads.

Image - http://s26.postimg.org/kyh3kigll/manual_fan_control.png

 

[setter]

I took all my fans bar cpu/cpu opt off mobo headers and use a fan controller instead. Have 9 case fans so there wasnt enough headers.

 

[doyll]

Asus has a history of saying headers are PWM when they are not.Some motherboards say they are PWM, but are 12v PWM on pin 2, not PWM signal on pin 4. .. they pulse the 12v they send to 3-pin or 4-pin fans, not a PWM signal the PWM fan needs to pulse a constant 12v power source.

 

[NeilF]

I took all my fans bar cpu/cpu opt off mobo headers and use a fan controller instead. Have 9 case fans so there wasnt enough headers.

N I N E !

Anyway, I hope you can see the fan control on the Z97-A is pretty clever You seem to have total control over every header

 

[setter]

There are similair settings for fan control in the bios of the formula too, or alternatively asus ai suite in windows. But the latter software caused issues with my keyboard disconnecting. My case also has the phanteks PWM hub, but seeing as i had a 30w per channel fan controller, (akasa FC6) i just decided to use it.

 

[NeilF]

There are similair settings for fan control in the bios of the formula too

Oh! I looked in its manual and couldn't see the ability to switch headers between PWM and DC, and also actually draw temp/speed graphs for each individual fan...

Must have missed it.

 

[NeilF]

Sounds like on the Z97-A you can do a pretty stunning job with the fans!

To make the most of full PWM control on all fan headers, fan calibration and fan curve adjustment were both added to UEFI, as well as the ability to map different fans to different heat sensors on the motherboard. This allows end users to take advantage of advanced cooling, regardless of operating system.

Fan Xpert 3 has also gotten an upgrade.

Along with fan calibration and fan curve adjustment, users will be happy to find that once a fan is calibrated, a lookup table is populated which provides fan RPM at regular power/duty cycle intervals. This helps take the guesswork out of planning fan curves, since many fans do not follow a linear progression. users can even set spin up and spin down times for fans, to ensure that brief increases or decreases in temperature are not accompanied by frequent changes in fan RPM.

Another image - http://img.hexus.net/v2/motherboards/intel/Z97/Asus/Z97A/stuff/B2B.jpg