Dual CPU fans off of one header?

[AUGieDogie]

OK so i run a dual fan heatsink on my CPU. Right now I have it running off of the CPU header and a chassis header. I'm trying to figure out how to get them to both run off of the CPU header. My boards specs list that header as able to handel 1 watt, and my two fans together would run below that. So if I just splice the wires from both fans into the one connector will it work? I'm worried about if the PWM will work correctly and if the Speed will Read correctly.

If not is there some sort of circut that I could build that would mimic the pwm to the chassis fans 3 pin using a 4 pin fan?

Thanks

AUG

 

[dawp]

http://www.frozencpu.com/products/1...litter_Cable_AK-CBFA04-15.html?tl=g47c251s636

 

[N4n45h1]

Out of curiosity, will the motherboard be able to correct determine the fan speed with one of these splitters?

 

[AUGieDogie]

I was wondering that myself.

dawp thanks for the link

 

[Kenmitch]

Out of curiosity, will the motherboard be able to correct determine the fan speed with one of these splitters?

I've never used one but I'd think as long as the fans are a matched set it should be able to. If they are grab bag as in diff speeds I could see it as being an issue.

 

[metril]

It won't be able to determine the correct speed. Also, I would not hook up more than one fan to the motherboard connector. The motherboard connectors are designed with one fan in mind. They are meant to provide at most a set amount of power.

Also, the fan speeds are determined using a third lead. This lead measures a residual current, which changes based on the RPM of the fan.

 

[AUGieDogie]

My motherboards manual stats 1A (12 W) max listed for the cpu header. If i remember right my fans pull like .22 Amps each.

Its not such a big deal, I have my second fan running off of the chassis header. Its just that its so nice and quiet when my cpu fan is at like 400 rpms. (chassis stays at like 1500)

 

[mv2devnull]

Also, the fan speeds are determined using a third lead. This lead measures a residual current, which changes based on the RPM of the fan.

Yes. On the splitter the "speed sensor" is connected to only one fan. Therefore, the motherboard senses the speed of that fan only. All fans receive the power/PWM.

 

[dawp]

I haven't used the PWM version but the normal 3 pin one has the speed detection on coming off one fan and the other just has power and ground, I'd imagine the PWM is similar.

I know my board, the one in my sig, can handle 2 amps(24 watts) on the cpu header so it could handle 2 fans with no problem as long as they're chosen correctly and don't draw too much power.

 

[mv2devnull]

It is. For example the Thermalright Silver Arrow includes two TY-140 PWM fans and such splitter cable from them.