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Dual 4pin CPU fans to single motherboard 4 pin connector

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October 1, 2010 8:48:37 AM

I have the CoolerMaster HAF X case and total of 8 (3pin) fans. Also I have the cooler master Hyper 212+ with 2 pull-push fans (4 pin). I have motherboard with 4 (3pin) connectors, and 1(4pin CPU) connector. Can I use Y splitter and connect 2(3pin) fans to each motherboard connector for the case fans?

Also, how do I connect the 2(4pin) CPU fans to the 1(4pin) motherboard header? Thanks
a b à CPUs
October 1, 2010 3:20:12 PM

Yes you can run a Y splitter and run 2 fans off of one header but if they also have a four pin molex you can connect them that way, and they would probably work better. Plug in 4 of the fans into the motherboard and the rest into molex. Plugging to many fans into the board can pull power that can be used for other things. So I wouldnt split anything other than the CPU fans.

For the cpu fans you can purchase a Y splitter to hook them both into the one header.
http://www.performance-pcs.com/catalog/index.php?main_p...
October 1, 2010 4:58:55 PM

There is an advantage to using a splitter over plugging the extra fans directly into the PSU which a lot of people don't talk about. Most motherboards today support advanced control and monitoring of the fan speed and voltage - if you plug a fan directly into the PSU you'll loose that control, so if possible I'd use splitters and keep the fans plugged into the mobo.
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a b à CPUs
October 1, 2010 5:05:12 PM

True, but it can only monitor on fan per header and the headers have amp ratings and to many amps could cause problems and shorten the life of the motherboard, also unless you have the option to control the fans in the bios for your system fans they will only run at one speed. Like I said to many is not good. Connect 4 fans on your motherboard and the rest to the PSU molex connectors. [:bohleyk:1]
a b à CPUs
October 1, 2010 5:16:54 PM

And only split your CPU fans.
October 1, 2010 5:18:16 PM

I've got several splitters on my motherboard to run about twice the fans it contains connections for. I've also got transient problems with windows freezing and very slow cold-boot. I'm about to RMA the motherboard (GA-P55A-UD3) - do you think using the y-splitters the way I am could cause these kinds of problems?
October 1, 2010 5:43:28 PM

Thanks guys for the replays. Yeah I preferred to use the mobo headers so I can monitor and adjust speeds, but I read on other places as well that the power may come short as D1RTYJU1C3 just conformed. I guess I'd plug the 200mm and 230mm fans directly into the PSU since they run on low RPM and are silent on MAX moving lots of air, and connect the small 120mm, 140mm and 80mm fans into the mobo for better control.

As far as getting the 4pin splitter for the CPU fan would that let me monitor and control them both the same way? They have PWM, so I want the mobo to regulate them itself and reduce turbulence as I've read happens when push-pull configuration is used with different fans/speeds and etc...
a b à CPUs
October 1, 2010 6:07:27 PM

They would both be regulated at the same time as if they were 1 fan, so as long as they are the same model they should work great.
I am pretty sure the amp rating for a CPU fan header is 2A so as long as the amperage max of the two fans dont exceed that you should be fine.
a b à CPUs
October 1, 2010 6:17:09 PM

livingegg said:
I've got several splitters on my motherboard to run about twice the fans it contains connections for. I've also got transient problems with windows freezing and very slow cold-boot. I'm about to RMA the motherboard (GA-P55A-UD3) - do you think using the y-splitters the way I am could cause these kinds of problems?



It is a possibility that the fans are causing it. Like I said each header has their own amp rating and if you surpass that rating it tries to pull more amps than what is available which creates heat and stress on the motherboard, not to mention it robs power from other components. So I would only connect 1 fan per header and see if that helps. [:bohleyk:1]
October 1, 2010 10:36:01 PM

This is what it says on the motherboard manual. The mobo supports those fan 4 headers and amps.

Processor fan 3.0 A
Front chassis fan 1.5 A
Rear chassis fan 1.5 A
Auxiliary rear fan 3.0 A


I have the Cooler Master HAF X case, My CPU-cooler is Cooler Master Hyper 212+, which came with 1 fan DC12V 0.36A and I added 1 more identical. So 0.36x2=0.72 which is way more than 3 A. This should work perfect right?

As far as the case fans I got

2x230mm - 0.40A
3x200mm - 0.28A
1x140mm - 0.14A
1x120mm - 0.15A +/- 10%
1x80mm - 0.04A

So would it be fine to connect more than 1 fan to 1 header, I prefer them all to the motherboard headers by using Y splitters, as long as they stay below 1.5A or 3A is the case.

For example

(2x230mm - 2x0.40A) + (1x140mm - 0.14A) + (1x80mm - 0.04A) = TOTAL 0.98A
All those 4 fans together are still below 1.5A, so will they run from this one 1.5A mobo header without any problems?

Thanks

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a b à CPUs
October 1, 2010 11:18:34 PM
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"My CPU is Cooler Master Hyper 212+, which came with 1 fan DC12V 0.36A and I added 1 more identical. So 0.36x2=0.72 which is way more than 3 A. This should work perfect right?"
.72A is less than 3A so you should be ok there

For the rest, if the ratings you posted are the Max amps than you should be ok.
But I would still personally only run 1 fan off of each header.
From what I can see though is the 200mm fans are probably .28A max a piece.
and the 230mm fans are .40A max a piece. The 120mm and 140mm could be right but I would think they would be more like .25A-.36A max.
But if you are sure they are the max ratings then you could try it but they seem low to me.
October 9, 2010 7:56:30 AM

Best answer selected by AlExAkE.
a b à CPUs
October 9, 2010 2:36:53 PM

Thanks, so what did you come up with, how did you set it all up.
!