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How to turn pwm fans off at idle - h170 |
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outlawz 
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Joined: 29 Sep 2016 Status: Offline Points: 3 |
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 Topic: How to turn pwm fans off at idle - h170Posted: 29 Sep 2016 at 5:17pm |
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Hello forum !!!
 I have build a new system and put 4 pwm raijintek fans in there to get a good airflow! My problem is that is seems there is no real control over the chassis fans, i have installed them of course on the pwm motherboard headers, and i tried from the uefi bios to make a nice curve with them being idle at start and start spinning after cpu reaches 60C but that wont happen fans spin all the time and their speed from HWmonitor : Fan 1 boreas 140m pc idle speed (should be 0) 390 rpm, ----rpm range from Raijintek webstite 600~1000 R.P.M. [PWM controlled] Fan 2 Aeolus 140m pc idle speed (should be 0) 770 rpm, ----rpm range from Raijintek webstite 650~1400 R.P.M. [PWM controlled] Fan 3 Aeulos 120m pc idle speed (should be 0) 390 rpm, ----rpm range from Raijintek webstite 400~1400 R.P.M. [PWM controlled] Fan 4 boreas 140m pc idle speed (should be 0) 500 rpm, ----rpm range from Raijintek webstite 600~1000 R.P.M. [PWM controlled] Also cpu fan is a Boreas 140m , which also spins constantly, starting at 470 rpm, besides having him start only when cpu is above 60c (like a gpu) Cpu temps are really low sitting at 30-40 degrees at idle and 60C under prime stress test! that's when all the fans are spinning at the rpm range shown above. I've tried 3 methods to work this out, - first making fan curves at uefi bios Fantastic setup, didnt not work at all.... all fans are spinning - second i tried the F-stream tuning utility , which is like uefi bios , but on windows... and did absolutely nothing at all.. - third option was speedfan which i know how to setup from previous pc , but somehow wasnt supported by the asrock h170 perfomance fatal1ty hyper motherboard that i've got. Speedfan could not give me acces to pwm headers and didnt have that option "software controlled" neither the "manual" option worked since even when i was tuning fans to 0% spin , nothing would change , except! the gpu fans...  which i already control through gpu software...I dont want to use an external pwm controller, since i want the fans to speed up automatically when temperature is rising! having the fans stop at idle whould make the pc so much quieter, basically silent! , gpu and psu have that mode and at idle their fans dont turn at all, but all the pwm headers of the motherboard make my fans spin all the time ! making the pc non silent , i wish there is another way to control fans and make them stop! since my cpu G3900 can be passively cooled at idle with the enormously huge Raijintek Tisis cooler.... Hope you have some ideas so i can try to make fans turn off!!! thanks for reading !!! |
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parsec
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Joined: 04 May 2015 Location: USA Status: Offline Points: 4996 |
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Posted: 23 Nov 2016 at 9:27am |
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After testing the various fans on my ASRock Z170 board, both PWM and three pin voltage controlled, using my board's A-Tuning utility, the minimum speed I could set the fans at was their 10% speed, as shown after running the FAN Test function that is available for each fan.
That is, after setting the fan speed % to zero. I set the temperature (vs fan speed) high enough so the CPU temperature would not influence the fan speed. So the reality of the fan speed control, as far as I can see, is while there is a zero fan speed setting, the actual minimum fan speed possible is 10%. The minimum fan speeds you posted seem to be the same, a bit lower than the fan speed specifications, but certainly about as low a PC fan can operate. Franky, the ability to completely turn off a PC fan with a board's fan speed control is virtually non-existent. I've never owned a mother board whose fan speed control allowed turning off a fan completely. Actually, some older boards I've owned would issue a fan speed warning when the PC started, if the fan on the CPU Fan header was less than ~500 RPM. There are multiple reasons why the fan speed control on mother boards does not allow a fan speed of zero. There are no standards for the minimum speed of a fan, their starting voltage, or speed (RPM) vs voltage or applied PWM signal level. All fans have different minimum speeds, but more significantly, have different minimum starting voltages. Dealing with the range of minimum and maximum fan speeds, and different starting voltages with all the fans that could be used is difficult. But the biggest problem with low or zero fan speed settings, is the starting voltage of a fan (the minimum voltage applied to a fan that will cause it to spin) is greater than the voltage needed to maintain the minimum fan speed possible. It takes more voltage sent to a fan's motor to initiate spinning, than it does to maintain the minimum speed of a fan that is already spinning. So we would think, simply apply more voltage to a non-spinning fan, to get it started. Doing that is not as easy as it sounds. Since the starting voltage of fans are not the same, the difference between the minimum spinning voltage and starting voltage of a fan may be as much as three to five volts, but as low as one or two volts. If the minimum fan speed voltage is much lower than the starting voltage, then the fan will suddenly begin spinning at a rate that will be higher than the minimum fan speed expected. Then the fan voltage should be reduced, to match the minimum fan speed possible. But how much do we reduce the voltage, without going below the minimum fan speed voltage? This situation leads to fan speed "pumping", where the fan becomes audible when it is forced to start, but then reduced again to a lower speed. That is a simplification of only two factors related to the difficulty of providing zero fan speed control. Finally, mother board manufactures are reluctant to provide zero fan speed control, assuming it is even possible. If a CPU or other components over heat due to the user using zero fan speeds, guess who gets the blame? It's not the user. So sorry, we simply cannot turn off the fans completely with automatic fan speed control. If you want to do that, you'll need a manual fan speed controller. Also, if your fans are audible at their 10% speed level, then they have a very high minimum speed. The minimum fan speeds you listed in your post should be inaudible, or so close to it that the difference between 10% speed and zero, should be inaudible. |
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outlawzgr
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Joined: 22 Nov 2016 Status: Offline Points: 12 |
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Posted: 23 Nov 2016 at 3:18pm |
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Hey Parsec
You are the Man! thanks for all that info, i know you are an asrock guy and i am too , as you can see love my board works well , cost so little and even overclocks every damn cpu (cant wait to test an kaby lake there) but let me inform you that asus motherboards , can stop chassis fans via their fanxpert suite. i understand what you've written and i know some things about voltages dont worry you are correct ,but somehow asus does this , now only throught motherboard headers , now asus does this through gpu 4-pin headers, the fast stop and only start at a specific temp you get to choose as for my fans, they are raijintek as you saw , aeolus and boreas the do spin at their 10% if you make the test in A-tuning the speed rated at 0% are the 10% speed like you stated , but the pc makes noise i think i have a goot pc case (i've build it myself) with lots of Bequiet fabric to make it even quieter , but the massive 140 fans push so much air that i can hear some "wind" going on inside the case. anyway thats a diffrent story , since motherboard cannot stop them i will try to hook them up my 1060 strix via Y-cable and see what happens :D !!!! |
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Xaltar
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Joined: 16 May 2015 Location: Europe Status: Offline Points: 25028 |
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Posted: 23 Nov 2016 at 3:36pm |
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The H170 Performance/Hyper is a great board, I love mine too
 I find it amazing how many high end features it incorporates at such a low price point. Sadly full stop on the fan headers isn't one of those features. This isn't an issue in my usage scenario but for some users, like yourself, it would be nice to have a true 0v option that stops the fans completely. When I want my fans dead silent I use a fan controller or, individual fan controllers like this:  I just remove the control knob from the slot cover and mount it in my case somewhere out of sight
 Not all that helpful if you want the fans to respond to temps though..... |
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parsec
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Joined: 04 May 2015 Location: USA Status: Offline Points: 4996 |
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Posted: 24 Nov 2016 at 12:23am |
I understand, but I never said it was not possible to shut fans off with automatic fan speed control. Just difficult, and when those fans do start up on the Asus board, you'll know it, since I can guarantee you they won't be running at their minimum speed at first. Guess which board would give me the CPU fan low speed warning? My Asus SaberTooth X58. Be careful using a Y cable on your video card, unless it is PWM controlled, and has a separate power source for the fans. PWM multiple fan splitter cables usually have a molex power connector, since drawing too much power from a fan header is not a good idea, it can damage it. The fan header on your video card was designed to power the fan(s) on the card only, and unless your fans are very low power usage models, like Noctua fans that are usually under 0.1 Amp, you may over load the video card's fan header. |
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parsec
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Posted: 24 Nov 2016 at 12:44am |
Ah, a Scythe fan, my all time favorite fans overall. Including the famous Servo Gentle Typhoons, and the GT PWM fans included with Mugen series coolers. I still use them. |
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Xaltar
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Posted: 24 Nov 2016 at 1:53am |
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I have a Scythe fan sitting in my 700w Zalman PSU that I swapped in there because it moves more air at lower RPMs than the horrible one that came with it
 Also the name, the name is awesome 
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outlawzgr
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Joined: 22 Nov 2016 Status: Offline Points: 12 |
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Posted: 04 Dec 2016 at 1:16am |
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I've contacted Asus and the fan headers (pwm controlled) of the gpu give 2 amps each,
i also contacted raijintek and they told me their fans consume 0.2 min - 0.45 max amperes so i am planning to hook up 3 fans in each header, they will run at 50% when activated so i guess they will consume less than 1 ampere, the header offers 2a , so i guess its ok !? |
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Pir8Radio
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Joined: 11 May 2024 Status: Offline Points: 15 |
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Posted: 11 May 2024 at 12:53am |
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I know this is an old topic, but even today I have ran into this same issue. My fans don't really need to be running and most fans that support the 0db mode are ugly, ?? But I ended up finding this jobbie that works great! Once the fan controller or motherboard PWM signal drops below 10% this thing shuts off power to the fan, killing it.. ha, guess thats why they call it the fan sniper. Just posting for anyone else looking for an answer.. This is the post that came up on google for me, so. https://fansniper.com
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outlawzgr wrote: