Is there a reason to get Voltage over PWM? - Overclock.net

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post #1 of 35 Old 06-14-2016, 06:34 AM - Thread Starter
 
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If 2 140mm fans are priced the same and the only difference is pwm or voltage control is there any reason to go for the voltage one over the pwm?

these are the fans:
http://www.newegg.com/Product/Product.aspx?Item=N82E16835709023
http://www.newegg.com/Product/Product.aspx?Item=N82E16835709022
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post #2 of 35 Old 06-14-2016, 06:36 AM
 
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If using a fan controller then voltage, if using pwm mobo (if its a true pwm fan header) then pwm. Supposedly its bad to control pwm fans with voltage control.

My spare hp had the cpu fan stop working, testing it i found out that it was working but the pwm circuitry probably wasnt anymore so i unplugged that pin and run it power/ground/sense.
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post #3 of 35 Old 06-14-2016, 06:38 AM - Thread Starter
 
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Quote:
Originally Posted by bluej511 View Post

If using a fan controller then voltage, if using pwm mobo (if its a true pwm fan header) then pwm. Supposedly its bad to control pwm fans with voltage control.

My spare hp had the cpu fan stop working, testing it i found out that it was working but the pwm circuitry probably wasnt anymore so i unplugged that pin and run it power/ground/sense.

I'm using an asus z170 pro gaming and it says all the headers are pwm.
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post #4 of 35 Old 06-14-2016, 06:54 AM
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Only CPU_FAN & CPU_OPT are true PWM. The 3 System fan headers are voltage control. Note in the manual that the 4th pin is listed as +5V. That's your giveaway. In my limited experience, PWM fans typically run fine voltage controlled. That said, unless you're attached to the white blades, the correct answer is to buy the voltage controlled ones with the black fan. They're $5 cheaper. http://www.newegg.com/Product/Product.aspx?Item=N82E16835709046&cm_re=ph-f140sp-_-35-709-046-_-Product

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post #5 of 35 Old 06-14-2016, 07:04 AM
 
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PWM and Voltage are technically equal to each other imho.
Both have their advantages, but they only work as good as your controller is. You should always proceed from your controller that can either handle 3-Pin Voltage or 4-Pin PWM or even both. And keep in mind that there are some vendors (mostly MSI and Gigabyte) with "fake" 4-pin headers that can only provide voltage regulation.

Regarding min. RPM:
PWM is not necessarily superior in this categorie because it always depends on A) how good the fan and B) how good your controller is (how wide the range is you can lower the voltage or PWM in %). Since I have tested a lot of fans on my Aquaero 5 I can say that most of the voltage fans (even very cheap models) can be throttled down to 3,0 to 3,5 volts(!) whilst PWM fans do have varying ranges from about 45% to 20% in the best cases.

That said PWM has the inherent risk of suffering from commutation noise which expresses itself in a rattling bearing noise. Such issues can appear when the constant shifting between 0V and 12V of an (unsmoothed!) squarewave signal genereate cyclic, fitful impulses of the blade. This phenomenon will not appear with a constant voltage.

But in the end it all depens on the quality and features of the fan and the controller being used to power it.
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post #6 of 35 Old 06-14-2016, 07:39 AM
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PWM is better and a more efficient use of energy / power, when it is done properly.
  • PWM uses pulsed power while variable voltage generates heat reducing the voltage from it's source 12v.
  • PWM has the ability to run at lower speeds than variable voltage because it generates full torque every time power is applied (which can sometimes create the clicks and rattle).
The above are the reason industrial motors are now mostly PWM and not variabable voltage.

I agree with Dr Strangelove, PWM is only as good as the PWM controllers, but there are 2 control components involved; the one built into the fan and the one fan plugs into.

While computation noise can be a problem, the power pulses can be done so there is no noise .. be it in the bearings, fan blade vibration, power surge, etc. As Dr S says, it's not a problem if the start/stop pulse is rounded,

PWM fans will also run with lower than 12v power, which means they will run at a correspondingly lower RPM range.

I guess TY-147A is a one of these 'best cases', because it's PWM control is from just under 300rpm to 1300rpm. tongue.gif

The short answer,PWM is preferable, but it really on what your computer system can properly control .. and what what the fan prices are.

post-flame-small.gifPhanteks Owners Club post-flame-small.gifpost-flame-small.gifWays to Better Cooling post-flame-small.gif
post-flame-small.gif1. Controling PWM Case Fans post-flame-small.gif2. Optimizing Case Cooling post-flame-small.gif3. Cooler Size Comparison & Cooling Comparison
post-flame-small.gif
=i7 980 @ 3.55GHz =PH-TC14PE w/2x TY-143 fans =Crucial Ballistix 3x4GB =GA-X58A-UD5 =ASUS GTX580 DirectCU II =Enermax Modu84+ =Define R2 w/3x TY-140 case intake fans; all PWM controlled by CPU fan socket
Phanteks Enthoo Primo MoBo Rampage III Extreme CPU i7 980xCooler R1 Ultimate w/ TY-147A fans RAM Dominator GT 6x2GB GPU ENGTX580 DCUII PSU Corsair TX850 Case [/COLOR]Phanteks Enthoo PrimoBase custom caster base
=i7 980X @ 4.0GHz =R1 Ultimate w/2x TY-143 fans =Dominator GT 6x2GB =Rampage III Extreme =ASUS GTX580 DirectCU II =TX850 =Enthoo Primo w/ custom castor base
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post #7 of 35 Old 06-14-2016, 07:56 AM - Thread Starter
 
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Quote:
Originally Posted by dlewbell View Post

That said, unless you're attached to the white blades, the correct answer is to buy the voltage controlled ones with the black fan. They're $5 cheaper. http://www.newegg.com/Product/Product.aspx?Item=N82E16835709046&cm_re=ph-f140sp-_-35-709-046-_-Product


Yeah i know about that, although when you buy 2 of the other ones it only comes out to about $4 more.
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post #8 of 35 Old 06-14-2016, 08:05 AM
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Quote:
Originally Posted by Tylerr View Post

Yeah i know about that, although when you buy 2 of the other ones it only comes out to about $4 more.
Shop around, prices vary a lot between retailer. Phanteks site sells too and sometimes have some good package deals.

Have you looked at the PH-F140MP? It's really a good fan too.

post-flame-small.gifPhanteks Owners Club post-flame-small.gifpost-flame-small.gifWays to Better Cooling post-flame-small.gif
post-flame-small.gif1. Controling PWM Case Fans post-flame-small.gif2. Optimizing Case Cooling post-flame-small.gif3. Cooler Size Comparison & Cooling Comparison
post-flame-small.gif
=i7 980 @ 3.55GHz =PH-TC14PE w/2x TY-143 fans =Crucial Ballistix 3x4GB =GA-X58A-UD5 =ASUS GTX580 DirectCU II =Enermax Modu84+ =Define R2 w/3x TY-140 case intake fans; all PWM controlled by CPU fan socket
Phanteks Enthoo Primo MoBo Rampage III Extreme CPU i7 980xCooler R1 Ultimate w/ TY-147A fans RAM Dominator GT 6x2GB GPU ENGTX580 DCUII PSU Corsair TX850 Case [/COLOR]Phanteks Enthoo PrimoBase custom caster base
=i7 980X @ 4.0GHz =R1 Ultimate w/2x TY-143 fans =Dominator GT 6x2GB =Rampage III Extreme =ASUS GTX580 DirectCU II =TX850 =Enthoo Primo w/ custom castor base
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post #9 of 35 Old 06-14-2016, 10:04 AM
 
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Sorry for the OT but as asus only gives us true pwm on cpu and cpu_opt is there another manufacturer that has true pwm on all the fan headers on the mb, since I fail to see the point of other headers if u cant control em to your desire.
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post #10 of 35 Old 06-14-2016, 10:22 AM
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