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QUestion on push & pull fan speed

Last response: in Overclocking
January 28, 2012 1:55:20 PM

I like to get some answers here & on some other sites about push & pull fan speeds. So I like to ask the experts for some answers...

I have (6) Enermax T.B. Silence Red Lightning non-PWM (3 wire) 120 mm silent fans (rated at 1,200 rpm) that I'm trying to control. I got an Aerocool V12XT touch LCD fan controller. It will only control (4) fans so I decided to control the (2) push & pull non-PWM fans on the radiator to my CPU liquid cooling loop & the other (2) push & pull non-PWM fans on the radiator to my video card liquid cooling loop. This (4) non- PWM (3 wire fans) that are connected to the touch LCD controller are also connected each with special tachometer wires to my CPU (I managed to get this tachometer wires from a special source as Aerocool only provide 1 with tachometer wire). All this fans that I used I can monitor the speeds on the BIOS as will as on Windows including those connected to a special fan controller.

The problem is with the (2) fans, one connected to the 3-pin power fan connector & the other connected to the 3-pin channel fan connector on my motherboard. There must be some reasons why motherboard makers only use 3-pin connectors for power & channel fans but let's say I wanna control this non-PWM fans. There's probably (3) ways for me to control this (2) non-PWM fans.

1) Using a separate fan controller but I don't like to do this.
2) Using a PWM fan (which I have but rather not use hence I like all fan matched).
3) Adding a splitter wire to control each of the (2) push & pull silent fans connected to a single fan controller input thereby leaving me with (2) fan controller inputs to my touch screen LCD fan controller for me to use for my (2) power & channel fans.

If I do the third, each of the push & pull fans will be on same speed as this push & pull fans are connected to a single fan controller input. Will there be a problem having the same push & pull fan speed or it has to be at variable speed to achieve better performance? Is it really necessary to control the power & channel fan speed or keep it at constant speed to achieve better performance? As I said above there must be some reasons why motherboard makers only use 3-pin connectors on power & channel fans.

I want an honest answer on this question. No graphs please.
a c 324 K Overclocking
January 28, 2012 9:30:28 PM

Just splice the extra fans to one of the fans on the controller so you'd have 2 fans on 1 channel. Either that or find some of those molex fan controllers on FrozenCPU and other sites that offer a dial knob for controlling a fan.

You aren't going to get any difference if you run 3 fans a few 100 rpm's different than others. In all honesty, it's kind of a pain in the ass to keep dialing them up and down and trying to get them all to be 'the same'. My KazeMaster fan controller allows me to monitor RPMs, but I never even look at it...I just dial them up and down as I see fit. They are either all the way pegged at 100%, or I just dial them down to whatever sounds low enough for me and still get good temps.
January 28, 2012 10:26:32 PM

So it really doesn't make any difference if the 2 fans in a push & pull configuration have same speed settings. I thought that the push fan has to be set a little bet higher than the pull fan hence there's a little resistance on the air being push as it hits the radiator fins.

Would it be best if I just leave the power & channel fans connected to the motherboard & running at constant full speed without having something to control the speed?
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Best solution

a c 324 K Overclocking
January 29, 2012 5:25:33 PM

If you run push/pull, it helps to have the fans close to the same speeds but even if not, the worst is you'll get some excess noise in some instances.
January 29, 2012 8:25:14 PM

Best answer selected by Cheaptrick.
January 29, 2012 8:27:09 PM

Good enough, I'll just keep the push & pull fan on (1) fan speed control pin.
a b K Overclocking
January 29, 2012 10:36:07 PM

This topic has been closed by Mousemonkey