Is there a way to adjust fan speed?

jepherz

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Jul 13, 2008
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I have 3 fans in my computer and my cpu fan which: XIGMATEK HDT-S1284EE 120mm Rifle CPU Cooler (or atleast it looks like that, theres a few xigmateks that look exactly the same on newegg so im not sure) it says the fan runs at 800 - 1500 RPM, and its a big fan. I don't know how fast its really running, but its quiet.

My other 3 fans are just the small regular case fans. 1 of them is connected to the mobo, its a 3 pin and it runs at around 800 rpm, thats quiet. but the other 2 are plugged into molex and run at around 1400 rpm, those are kinda load....is there a way i can slow them down?
 

einstein4pres

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You can reduce the voltage with a little bit of wiring. Instead of running 12V and ground, you can run 12V and 5V, which reduces the voltage to 7V and slows down the fan.

There are also fan controllers that you can buy.
 

montyuk

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essentially the wire has a mini resistor in it to reduce the voltage,
no idea which one it is, look on ebay for prices aswell, maybe someone on there can do you a deal and combine the postage.
 

Kari

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hmm that can't be good for your psu, using the 5V line as ground, the currents would go into wrong direction on that line... sounds suspicious anyways, maybe the psu can take it, IDK...
 

jepherz

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hmmm, some websites are saying what Kari is saying when I googled this up.

I have another quesiton then...The fans I bought were 28dba according to newegg. They were like 2 dollars each shipped or something. Do the more expensive ones around 8-9 each or more that say they run 80% quieter really run quieter and work just as well?
 

Steffno

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If you have a new motherboard, you might be able to controll the fans with SpeedFan (www.almico.com/speedfan.php).
 

rexter

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What you need is a resistor with 50 ohms 5% tolerance @ 2.5 watt, cut the black wire and connect each end of the resistor and that's it. Icreasing the resistance value will decrease the fan speed, but will not see the difference unless the change is by the hundreds. This is base on 230 miliamp of fan.

Or like einstein4pres suggestion use 5 volts.

The yellow wire is 12 volts, the red wire is 5 volts and the two black wires are ground. So all you need to do is extract the pin from the molex that goes to the fan and move it to the other end of the slot where the red wire go.

Note that if you have slave wire connected to the fan molex connector, the voltage will also be 5 volts positive so DO NOT connect the molex back to the power supply terminal or you will short the wire and also make sure that you do not reverse the polarity of the wire.
 

jepherz

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My mobo is a Gigabyte GA-EP35-DS3P. will that work with speedfan? my quiet fan is running at 1500 according to that program and my noisy one is at 3000rpm.

how do you lower it with speedfan? Do i just press the down arrow to lower the percentage to 50%? is thats all you have to do, then im guessing its not working for me =[
 

rexter

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You have to do an experiment on that yourself because when I tried it on my asus board; it didn't do quite well. So I end up using the program provided by the company, but I think speed fan only works for CPU fan though.

Check your installation disc if it has a program that'll allow you to control the fan speed.

 

rexter

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One other thing you might want to try is to put the two fan together in series, this will devide the 12 volts between the two fan giving 6 volts each fan. This connection will not allow you to control the fan speed though.

Anyway good luck with your findings.