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PWM or DC on Motherboard Setting?

BKL
By BKL
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I have the ASUS Rampage Extreme V.  In the BIOS setup I have the option of setting various fans to PWM or DC.  All fans are PWM capable, athough some connect to a fan splitter.  What should I choose in the BIOS setting?

 

Also, I noticed that not all of my fans are operating, although they are plugged in and work.  Is there a reason why they might not be running - I believe it could just be that the mother board only turns certain fans on at certain speeds.  Is there a way to test to fans via BIOS or Windows to see that they do in fact all respond?

 

Thanks!

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PWM is the same as DC when put trough a RC filter, so it does not matter.

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Any thoughts on why some fans are on and some fans are off?  Will the MB control these?

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I have the ASUS Rampage Extreme V.  In the BIOS setup I have the option of setting various fans to PWM or DC.  All fans are PWM capable, athough some connect to a fan splitter.  What should I choose in the BIOS setting?

 

Also, I noticed that not all of my fans are operating, although they are plugged in and work.  Is there a reason why they might not be running - I believe it could just be that the mother board only turns certain fans on at certain speeds.  Is there a way to test to fans via BIOS or Windows to see that they do in fact all respond?

 

Thanks!

I would set to pwm if all of your fans support it, or at least the ones that do.  I dont know what an RC filter has to do with anything here ^ but I'd be interested to find out.   having them connected to a splitter should not be a problem as long as it is a PWM splitter (has connections to the 4th pin on both fan ports

 

If not all the fans are spinning they may still be getting power but not enough to run them.  do they spin up when you turn the pc on?   the monitoring section of Asus bios has all the fan control options but the also support fanxpert 3 which can make it easier to adjust your fan curves/settings

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Any thoughts on why some fans are on and some fans are off?  Will the MB control these?

I dont think that your motherboard would turn any fans completely off by default

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Select the PWM option. Make sure you have a PWM splitter. DC is basically voltage control.

Find a working fan then locate the specific port. Try plugging the fan into a working PWM port. IF the fan spins that previously didn't, try downloading ASUS's control center which allows you to control your fans and setup fan curves. Speedfan is also great. Just read the documentation on how to set that up.

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Select the PWM option. Make sure you have a PWM splitter. DC is basically voltage control.

Find a working fan then locate the specific port. Try plugging the fan into a working PWM port. IF the fan spins that previously didn't, try downloading ASUS's control center which allows you to control your fans and setup fan curves. Speedfan is also great. Just read the documentation on how to set that up.

OK, as an FYI, I have 14 fans and 4 radiators, I'm water cooling the entire system.  My temp is 29 degrees C.  Not sure if those stats make a difference.  The fans all did work upon initial setup and during the first few boot-ups.  Now that I installed my OS and I'm "settling in" to using the computer, I noticed that they are not all on all the time. 

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OK, as an FYI, I have 14 fans and 4 radiators, I'm water cooling the entire system.  My temp is 29 degrees C.  Not sure if those stats make a difference.  The fans all did work upon initial setup and during the first few boot-ups.  Now that I installed my OS and I'm "settling in" to using the computer, I noticed that they are not all on all the time. 

 

Try speedfan. That way you can see if it's a temp "issue" or the fans are actually broken. None should stop spinning when an OS is installed unless someone mucked with the BIOS.

blackshades on

 

 

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OK, as an FYI, I have 14 fans and 4 radiators, I'm water cooling the entire system.  My temp is 29 degrees C.  Not sure if those stats make a difference.  The fans all did work upon initial setup and during the first few boot-ups.  Now that I installed my OS and I'm "settling in" to using the computer, I noticed that they are not all on all the time.

Sounds like mobo has some automatic control going on. So with PWM fans mobo detects low CPU temp and turns some of the fans down. Like those connected to CPU_OPT header.

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