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Case fan speed managed by splitter

Last response: in Overclocking
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July 22, 2012 11:05:34 PM

Okay, here's the deal. I have a GA-MA770T-UD3P mobo, and as far as I can tell, only the cpu header provides control via EasyTune6. I think you may be able to do voltage but not PWM to control fans put into the system headers via speedfan i(f google is correct, haven't tried yet). Either way I'd prefer to have the case fans speed decided by cpu temp, so I don't have to constantly fiddle with speedfan/controller knobs.

Anyways, my question is this. Would I be able to get the desired result using the rosewill pwm splitter followed by two 3 pin splitters to power my 4 case fans and hs fan according to cpu temp. The splitters in question:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Thanks in advance!
July 22, 2012 11:27:25 PM

I think you would need a PWM splitter but I don't think there is such a thing (the PWM header should be 4 pin anyway right?)

I believe 3-pin fans wont work with this but I could be wrong.

How about Arctic cooling fans - the F1 range allows you to almost 'daisy-chain' PWM fans so the whole system runs from whatever PWM source you choose i.e. CPU or Graphics.
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July 22, 2012 11:37:02 PM

Huh, well I thought that the rosewill one (first link) was a pwm splitter. But I don't know much about the subject that's why I'm asking. It seems they were advertising that it was capable of doing so.

And could you elaborate on the Arctic cooling fans?
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July 23, 2012 12:08:28 AM

Sorry - didn't see the links. I make you right - PWM splitter in all its glory! I's been a while since I looked for something like that.

Arctic cooling fans do a similar thing. One fan plugs into the PWM motherboard fan header/socket, and then connects to the other fans...and they all run on PWM. Link:

http://www.tomshardware.co.uk/forum/267576-11-arctic-co...

It's called PST (PWM Sharing Technology) - a bit of Googling brings up loads of results if you're interested.
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July 23, 2012 1:08:58 AM

Oooh okay, cool, thanks man!
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July 23, 2012 2:18:55 AM

Okay, after a little research I think I understand this better. The rosewill splitter would still need 4 pin pwm fans to work. My mobo only has one case fan header that can control speed via 12v. So now I'm wondering, is there anything like the rosewill splitter for 3 pins? As in basically a 3 pin splitter that attaches to the header, but that circumvents the mobo and draws power directly from the psu. Now, that I think about it, that sounds kind of impossible, but a man can hope. Guess I'll probably just end up buying a fan controller, but I'd love to have automatic speed based on temperature.
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July 23, 2012 8:11:26 AM

No. I'm 99% sure that PWM control requires PWM fans. The 4th wire that PWM fans have, is for the controlling element. Without that 4th wire, there is no way the PWM header can control your fan.

You could just buy some PWM fans and sell the ones you have on eBay etc?
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July 23, 2012 4:50:15 PM

The first item, the PWM splitter http://www.newegg.com/Product/Product.aspx?Item=N82E168... would allow PWM control of three fans connected to this cable. You will notice only one of the three male connectors has all 4 pins. This is because the other two have the sense pin removed to allow only one fan to report it's RPM. But don't be confused by this because all three connectors will still work and control PWM fans.

Now, if you wanted to connect more PWM fans and decided on daisy chaining them you would just need to make sure anymore splitters you used had PWM connections (typically 4 pin).

With your cable management sorted, note that in order for this to work all your fans must be PWM fans (4 pin connecters).

Quick rundown on the pins located on fan connectors...
Pin 1 - Ground
Pin 2 - Power
Pin 3 - Sense (reads RPM of fan)
Pin 4 - Control (PWM signal)

So with that pin layout in mind. A 2 pin fan would run at full speed because it has only ground and power. A 3 pin fan would run at full speed and show its RPM. A 4 pin fan would do all the above but be able to change its speed via PWM control with use of the 4th pin depending on any given variable (typically temperature).

Side Note: 2 pin, and 3 pin fans can be controlled. But not by the method of PWM. They can be controlled by voltage regulation. So for example with a simple fan controller you could change the voltage supplied to a 3 pin from 12v to 7v and the RPM would drop to about half.

Hope I helped.
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July 24, 2012 6:33:18 AM

Best answer selected by taydee.
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