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2 fans in one PWM mobo connector

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a b K Overclocking
September 23, 2010 12:36:04 PM

Hello guys...... i have gigabyte GA-p55-usb3 mobo which was the following fan headers - one 4-pin CPU fan header, one 4-pin case fan header and two 3-pin case fan header (well one is for the psu fan but i'll use it for a case fan).

I was wondering if i can connect two PWM fans (for case cooling) into one 4-pin case fan header using a connector and still achieve PWM control with the correct volts reaching both the fans or the voltage will be split and the fans would be getting only half the intended volts.

a b K Overclocking
September 24, 2010 8:00:55 AM

Don't post multiple threads about the same issue.. I don't know about others, but it makes me just want to tell you to 'do one' and leave your threads untouched.

ANYWAYYYY...

Depends how the adapter is made whether they'll get the full current.

Your best choice would be to buy (or make) some 3pin to molex adapters as you can run them in a daisy chain and have your fans running at full speed. That's what I would do.
a b K Overclocking
September 24, 2010 5:24:55 PM

You can, BUT (1) Must cut the Sense (Reports RPMs) of one of the fans. and (2) Both fans will run are the same speed.

The sense line sends back a pulse indicating RPMs - Would get some really crazy readings if two fans are both sending a signal. Not only would this signal be sent to the motherboard, but also to each other fan.
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a b K Overclocking
September 26, 2010 7:22:01 AM

Noted acer0169 and will comply in future.

I dont want to run the fans to be running at full speed. This defeats the purpose of PWM fans. Like RetiredChief said i researched and found the following.

4 Pin Function Wire by Color (It could vary depending on manufacturer)
1 GND Black
2 12 V Yellow
3 Sense Green
4 Control Blue

So i have to cut the 3 sense green to one of the fan so that only one feedback is given to the mobo. I also founda few Y splitters offering the same config plus one offering connectivity for 3 fans (just the 4 control blue) and molex power for all fans (so that the power is drawn from the PSU and mobo voltage is not affected).

Point out if i missed something........... And thanks again............
a c 224 K Overclocking
September 26, 2010 8:07:03 AM

CAUTION: It would be better to use a fan controller powered directly from the power supply, to manually control the speeds of those fans, rather than overload the motherboard fan header which was only designed for the load of one fan per header.

I know a fan controller solution will cost you more than a Y split adapter pigtail, but in the long run may be much cheaper than replacing the motherboard.
a b K Overclocking
September 26, 2010 9:04:36 AM

@4ryan6 - I'm not planning to use the power supply for the PWM fans from mobo since they are designed for one fan use only (at least technically). I'm only gonna use 4 Control blue connection from my mobo's 4 pin fan header (the mobo has a seperate 4 pin system PWM fan header apart from the 4 pin CPU PWM fan header) to connect to the case fans (so that they are temp controlled by mobo). And the power for the case fans from the PSU (it requires only the 1 GND black and 2 12 V Yellow. This is daisy chained.

The splitter i have in mind is linked below.

http://www.newegg.com/Product/ImageGallery.aspx?CurImag...

Let me know your feedbacks
a c 224 K Overclocking
September 26, 2010 9:56:53 AM

^ That splitter will work just fine because the raw power to actually run the fans will be coming directly from the power supply itself, only signal input from the motherboard header.
September 26, 2010 1:57:27 PM

4Ryan6 said:
^ That splitter will work just fine because the raw power to actually run the fans will be coming directly from the power supply itself, only signal input from the motherboard header.


+1^
a b K Overclocking
September 27, 2010 7:17:15 AM

Thanks Guys........... great feedback.......... now if i could get some suggestion on some good PWM 80 mm case fans......... low noise, decent cfm and NO LED............

@ acer0169 - or should i start a new thread????????
a b K Overclocking
September 27, 2010 8:47:55 AM

Haha - I'm no mod, don't ask me. Just annoys me when people spam the forums up.

I'd suggest you have a look at quitepc.com. They have some VERY good fan choices of all sizes.
a b K Overclocking
September 27, 2010 9:12:29 AM

@ acer0169 - :)  OK thanks again...........
a c 224 K Overclocking
September 27, 2010 10:17:03 AM

You posted your adapter link from Newegg, they have quite an inventory of 80mm case fans in stock, if you're totally restricted to using 80mm fans they can get quite loud with the higher CFM fans.

I would suggest shopping and making your own decisions, there are so many possibilities you'll have to decide on sound levels and cfm airflow, keeping in mind there are companies that specialize in low noise high cfm fans but they do cost more.

Also keep in mind the connection points you have to the adapter, so you don't have to buy additional adapters to connect them, by overlooking that bit of info when deciding on the fans you want.

Hope that helps, I'm outa here. Ryan
a b K Overclocking
September 27, 2010 4:01:03 PM

Thanks Ryan............ I didnt want to do a trial and error with new egg's stockpile of fans.............. i thought someone could throw some light on personal experiences on 80 mm fans............ PWM to be precise............ i reasearched scythe fans are quite............ but nothing beats experience............. if anyone can help me out, i dont mind trying two brands...........
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