Overclock.net › Forums › Cooling › Air Cooling › question about PWM fans
New Posts  All Forums:Forum Nav:

question about PWM fans

post #1 of 8
Thread Starter 
hey guys,

i finally got a system coming together and the only thing left to solve is the air flow. i'm trying to figure out what fans to buy. my case is a corsair vengeance c70, and i got a h100 for my cpu so that will take care of the top. the back, side panel, inside, and front i will buy fans for. the question is i know that PWM fans are the ones you plug into controllers/mobo because it can change its speed. are the ones that plug into the psu directly just going to go at 100% all the time then?

if i bought a fan that wasn't a PWM and plugged it into the mobo, would it still work?

thanks hopefully you guys can clear it up for me biggrin.gif
Death Tyrant
(11 items)
 
  
CPUMotherboardGraphicsRAM
i7-3770k p8z77-v evga gtx 780 classified SLI corsair vengeance 16gb 
Hard DriveOptical DriveCoolingOS
ocz vertex 4 256 asus 24x corsair h100 windows 7 pro 64 
MonitorPowerCase
Overlord Tempest X270SE corsair ax850 corsair vengeance c70 
  hide details  
Reply
Death Tyrant
(11 items)
 
  
CPUMotherboardGraphicsRAM
i7-3770k p8z77-v evga gtx 780 classified SLI corsair vengeance 16gb 
Hard DriveOptical DriveCoolingOS
ocz vertex 4 256 asus 24x corsair h100 windows 7 pro 64 
MonitorPowerCase
Overlord Tempest X270SE corsair ax850 corsair vengeance c70 
  hide details  
Reply
post #2 of 8
Use PWM fans with Akasa and/or Gelid PWM spitters. These splitters use motherboard PWM control and PSU molex power. I use CPU_fan socket on motherboard and CPU cooler fan as master rpm control and all other fans use the same PWM signal to control their rpm. As long as all of your fans are similar rpm range all will spin at similar rpm.thumb.gif

I compared Thermalright TY-140 (700-1300rpm) and TY-143 (700-2500rpm) at same PWM signal

TY-140 635 800 860 915 975 1010 1080 1110 1150 1215 1220 1270 1305 1330rpm
TY-143 605 800 950 1110 1260 1400 1550 1700 1850 2000 2150 2300 2400 2500rpm

As you can see up to 900rpm they are close to same rpm

TY-143 blew itself over at 1800rpm biggrin.gif
post #3 of 8
Thread Starter 
so do i just buy a pwm fans for all my fans on the case? including the ones at the front and side that i attach directly to the PSU? cause im sure the mobo has no room for 7 fans

or do you mean that the splitters themselves will control the other fans?
Death Tyrant
(11 items)
 
  
CPUMotherboardGraphicsRAM
i7-3770k p8z77-v evga gtx 780 classified SLI corsair vengeance 16gb 
Hard DriveOptical DriveCoolingOS
ocz vertex 4 256 asus 24x corsair h100 windows 7 pro 64 
MonitorPowerCase
Overlord Tempest X270SE corsair ax850 corsair vengeance c70 
  hide details  
Reply
Death Tyrant
(11 items)
 
  
CPUMotherboardGraphicsRAM
i7-3770k p8z77-v evga gtx 780 classified SLI corsair vengeance 16gb 
Hard DriveOptical DriveCoolingOS
ocz vertex 4 256 asus 24x corsair h100 windows 7 pro 64 
MonitorPowerCase
Overlord Tempest X270SE corsair ax850 corsair vengeance c70 
  hide details  
Reply
post #4 of 8
What motherboard do you have?
If the MB has PWM (4 pin) fan headers then PWM fans will work normally.(duty cycle set in bios to control speed)
A PWM fan in a 3 pin MB fan header will spin at 100%.
A 3 pin fan in a PWM MB header can usually be controlled by voltage with bios or software.
Any fan plugged to the psu directly will run at 100%.


Gyro
My System
(14 items)
 
  
CPUMotherboardGraphicsGraphics
AMD Ph IIx4 955 @ 3.2 Asus M2N32-sli dlx Asus GTX 460 1gb DirectCU MSI GTX 460 1gb Cyclone 
RAMHard DriveOptical DriveOS
4x2gb OCZ ddr2 1066 plats seagate 320gb sata lg supermulti dvd WIN 7 64 
MonitorKeyboardPowerCase
acer p221w ms SS ST75F-P 750w CM 690modded w/KazeMaster pro 
Mouse
ms intellimouse explorer3.0 
  hide details  
Reply
My System
(14 items)
 
  
CPUMotherboardGraphicsGraphics
AMD Ph IIx4 955 @ 3.2 Asus M2N32-sli dlx Asus GTX 460 1gb DirectCU MSI GTX 460 1gb Cyclone 
RAMHard DriveOptical DriveOS
4x2gb OCZ ddr2 1066 plats seagate 320gb sata lg supermulti dvd WIN 7 64 
MonitorKeyboardPowerCase
acer p221w ms SS ST75F-P 750w CM 690modded w/KazeMaster pro 
Mouse
ms intellimouse explorer3.0 
  hide details  
Reply
post #5 of 8
My experience is 3 pin fans plugged into PWM sockets run at 100%. You need to change bios setting to voltage control instead of PWM control. Reason is that PWM socket has PWM signal, rpm senser, neutral & 12v leads. 12v lead is always 12v when using PWM. wink.gif
Edited by doyll - 9/2/12 at 5:36pm
post #6 of 8
it really doesnt matter if your fan is PWM or not, you can plug it in your mobo and it will work, the fan will speed up and slow down depending on the temps, this is if your mobo have fan speed control features. lots of mobo have only fan speed control with the CPU fan header, other fan header does not have fan speed control.

if you plug ANY fan, including PWM fan, directly to the PSU, there will be no speed control.

if you want, you can purchase a fan controller.

i will repeat, any fan can be speed controlled, not only pwm fans.

3 pin does not have pwm, 4 pin does have pwm.
post #7 of 8
Do keep in mind the motherboard is not designed to run high wattage fans or large number of fans.

Even PWM fans on splitter using PSU molex for power will only run 7 or 8 fans because the PWM signal isn't strong enough. I can get 9 working on my X58A-UD3R but 10 doesn't always work.
post #8 of 8
Thread Starter 
oh sorry my motherboard is asus-p8z77-v.

thanks fore the input guys!
Death Tyrant
(11 items)
 
  
CPUMotherboardGraphicsRAM
i7-3770k p8z77-v evga gtx 780 classified SLI corsair vengeance 16gb 
Hard DriveOptical DriveCoolingOS
ocz vertex 4 256 asus 24x corsair h100 windows 7 pro 64 
MonitorPowerCase
Overlord Tempest X270SE corsair ax850 corsair vengeance c70 
  hide details  
Reply
Death Tyrant
(11 items)
 
  
CPUMotherboardGraphicsRAM
i7-3770k p8z77-v evga gtx 780 classified SLI corsair vengeance 16gb 
Hard DriveOptical DriveCoolingOS
ocz vertex 4 256 asus 24x corsair h100 windows 7 pro 64 
MonitorPowerCase
Overlord Tempest X270SE corsair ax850 corsair vengeance c70 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Air Cooling
Overclock.net › Forums › Cooling › Air Cooling › question about PWM fans