if cpu and system running cool will PWM fan shut down?

newbuild

newbuild

newbuild

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i'm running temps between 21 and 29c on the cpu and system. on a couple of occassions the exhaust fan has stopped spinning - is this as a result of the system running so cool or a fault possibly?

i ask becuase when i went into the gigabyte app which controls the fans and did calibrate and then flicked between standard and silent modes it kicked again and stayed on...............
 
If you drive the fan with voltage rather than PWM then it is entirely possible that a PWM fan will stall or not start up.

Generally a PWM duty cycle of 20 or 30% will drive the fan at it's lowest rated speed and should start up because the 12v kick of PWM should overcome the inertia of the fan bearing.
 
Tealc said:
If you drive the fan with voltage rather than PWM then it is entirely possible that a PWM fan will stall or not start up.

Generally a PWM duty cycle of 20 or 30% will drive the fan at it's lowest rated speed and should start up because the 12v kick of PWM should overcome the inertia of the fan bearing.
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how can i check if the fan is running on pwm as opposed to voltage?
 
newbuild said:
how can i check if the fan is running on pwm as opposed to voltage?
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BIOS would be the best place to start looking I would think. There is sometimes an option as to the method of control over certain fan headers and also fan response values which you can change.
 
If your board is the one in your sig, then you only have one PWM fan header, the CPU_FAN header. The others (CPU_OPT and SYS_FAN1/2/3) are all voltage control.

Confusingly, they are all 4 pin headers anyway. This means that while they will drive PWM fans happily, they are not controlling them via PWM.
 
I've set my system up so that when idling or under very light load (i.e. browsing or downloading) none of my fans are spinning, even the ones on the rads. All 8 fans in my case are PWM.
 
amigafan2003 said:
I've set my system up so that when idling or under very light load (i.e. browsing or downloading) none of my fans are spinning, even the ones on the rads. All 8 fans in my case are PWM.
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What are you using to control them? Assuming PWM control, most will not allow the fan to stall, and a lot of software (I use asus Fan Xpert) will not allow you to set the fans too low. My mobo only has 2 PWM headers, and you can't control them individually. Two other headers are voltage control, and then there are 2 permanent +12v fan supplies.
 
abbotsmike said:
If your board is the one in your sig, then you only have one PWM fan header, the CPU_FAN header. The others (CPU_OPT and SYS_FAN1/2/3) are all voltage control.

Confusingly, they are all 4 pin headers anyway. This means that while they will drive PWM fans happily, they are not controlling them via PWM.
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so in that case and thank you for pointing this out i've gone and bought the wrong type of fans for my board, i actually asked gigabyte this questio about 3 pin and 4 pin fans. and they told me that the board was unable to adjust the speed of 3 pin fans but it was able to manage 4 pin PWM fans.

so how can i get around this now?
 
i am just using the gigabyte app which is not very good in my opinion. any suggestions on a 3rd app/software to ensure the fans are being managed and ran correctly.
 
You could get yourself a PWM splitter cable (or two) and have the PWM fans all controlled off the CPU_FAN header. I suppose Gigaybyte implement 4 pin fan headers so that all available fans will fit to their boards but it is cheap that they don't implement control circuitry for modern PWM fans at the same time.
 
Tealc said:
You could get yourself a PWM splitter cable (or two) and have the PWM fans all controlled off the CPU_FAN header. I suppose Gigaybyte implement 4 pin fan headers so that all available fans will fit to their boards but it is cheap that they don't implement control circuitry for modern PWM fans at the same time.
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doing ths wont have any sort of adverse affect on the fans or place stress on the board or anything?
 
newbuild said:
doing ths wont have any sort of adverse affect on the fans or place stress on the board or anything?
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Nope.

The PWM signal drives the mosfet on the fan and the power comes from a Molex connector. Theoretically you could daisy chain dozens of PWM fans off a single PWM signal.
 
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TBH, if you are happy with temperatures, there is nothing wrong with voltage control. It would be best to set it up so that the lowest speed keeps the fan spinning though.
 
abbotsmike said:
What are you using to control them? Assuming PWM control, most will not allow the fan to stall, and a lot of software (I use asus Fan Xpert) will not allow you to set the fans too low. My mobo only has 2 PWM headers, and you can't control them individually. Two other headers are voltage control, and then there are 2 permanent +12v fan supplies.
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Easytune.

Fans stop and start no problems.

Tealc said:
Nope.

The PWM signal drives the mosfet on the fan and the power comes from a Molex connector. Theoretically you could daisy chain dozens of PWM fans off a single PWM signal.
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Exactly what I'm doing - all rad fans get the signal from the cpu header and case fans get the signal from sys 3 (which is linked to case temp).
 
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If you want to be in control instead letting system do it for you, buy some cheaper fan controller.
I have some 25£ Lamptron with 6 4.5w channels and works wonders, only heatsink fans are pwm and connected to motherboard. Rest, I played a bit to see what is acceptable noise/performance speed, which turned up to be around 1100rpm. Temps are very nice and never had problems.
 
to be honest i think regarding this fan/cooling stuff i'm out of my depth can't get my head around it, and added to this is that sometimes my exhaust fan comes on sometimes it don't and that's same with the front two as well. which is making me feel paranoid.
 
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