how do i control PWM fans[?]

nyhcbri · Post by **nyhcbri** » Tue Feb 16, 2010 2:17 pm

i want to get these 92mm nexus PWM fans but how will i control the speed. i was told if there is no control they will run at full speed and thats not good. the asus motherboard has 4 pin Q-fan but that is only for the cpu. the case and psu headers are 3 pin. any thoughts?

grandpatzer · Post by **grandpatzer** » Tue Feb 16, 2010 7:27 pm

I connected a 3 pin fan to a 4pin cpu plug on my motherboard and it regulates it depending on heat.

the best way for you is to test with case open, maybe in bios motherboard support voltage/regulation or rpm/regulation?

however be careful with what you do!
I'm in no way a expert or well informed on this matter!

lodestar · Post by **lodestar** » Wed Feb 17, 2010 1:09 am

To control your PWM fans (sync them with the CPU fan) you need a PWM splitter cable. One that I have used is the Akasa, available for around $8 US from a number of places including http://www.frozencpu.com/products/10350 ... CB002.html.

If you want to control the maximum speed of the PWM fans you can combine the splitter cable with a PWM fan controller such as the Zalman PWM Mate. This should cost around $15-$16 US, and again is available from a variety of sources such as http://www.quietpcusa.com/Zalman-PWM-Ma ... 656C0.aspx.

nyhcbri · Post by **nyhcbri** » Thu Feb 18, 2010 5:46 pm

what do you think of this

http://www.newegg.com/Product/Product.a ... -_-Product

will it be effective in my solo case with the cpu fan, 120mm tri cool exaust, and a 92mm pwm intake. quiet is key for me

lodestar · Post by **lodestar** » Thu Feb 18, 2010 10:58 pm

Yes, that should be fine - it looks to be similar to/same as the Akasa item at about half the price.

ehume · Post by **ehume** » Fri Feb 26, 2010 1:56 pm

Check to see what comes in that Arctic cooling box. I got a 92mm PWM AC that has a wiring harness that allows you to control two or more fans with the WPM header. It even has a separate rpm wire so you can monitor the CPU fan's rpm along with the new fan's rpm.

nyhcbri · Post by **nyhcbri** » Mon Mar 01, 2010 9:36 pm

arctic cooling box????

ehume · Post by **ehume** » Mon Mar 01, 2010 10:15 pm

nyhcbri wrote:arctic cooling box????

Sorry. Got addled.

nyhcbri · Post by **nyhcbri** » Wed Mar 10, 2010 6:29 pm

ok so i have an update. i purchased a scythe kabuto and what a difference in silence. along with that i purchased a pwm splitter for the q-fan function on my motherboard.
http://www.newegg.com/Product/Product.a ... -_-Product

for the splitter i purchased a nexus pwm fan
http://www.newegg.com/Product/Product.a ... -_-Product

the problem is the scythe fan is a real quiet 1000rpm but the nexus using the pwm split under q-fan is 1900rpm and to loud for my taste. i tried plugging the nexus fan direct to the motherboard cpu input and the same 1900rpm. plugging the nexus fan into the motherboard chassis input gave me the full 2500rpm which was expected. why is the fan spinning so high its rated 700-2500 and the cpu temp is under 33c. any ideas?

lodestar · Post by **lodestar** » Wed Mar 10, 2010 11:38 pm

Asus motherboards ship with Q-Fan disabled as the default setting. The two Asus systems that I put together both had Q-Fan left at this setting because quite frankly I didn't even notice it was there. With Q-Fan disabled the PWM fan should work correctly, so I would say go into the Hardware Section of your BIOS and disable it.

nyhcbri · Post by **nyhcbri** » Thu Mar 11, 2010 4:03 am

no thats not it q-fan has been on

lodestar · Post by **lodestar** » Thu Mar 11, 2010 6:56 am

The problem I think is that the 2 PWM fans have very different specs, so that the motherboard signal is OK to run the CPU cooler fan quietly but runs the 92mm PWM fan too fast.

Solution: use the Zalman PWM Mate, already mentioned, to reduce the speed of the 92mm to an acceptable level. You can wire it to just the 92mm so it won't affect the CPU fan level. The PWM Mate only controls the maximum speed at which a PWM fan will run.