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Power Distribution for System Fans

Last response: in Systems
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September 14, 2010 2:23:12 AM

I am in the process of building a new system based on the Gigabyte GA-P55A-UD4P. The motherboard will be mounted in a CoolerMaster HAF X case.

The case has four fans and then there is the CPU cooling fan; for a total of five fans.

The CPU fan gets connected to the motherboard. Of course…… But, my motherboard can supply power to three other fans.

Right now, I have connected the rear and top fans to the motherboard. The front and side fans are connected directly to the power supply.

Should case fans be connected to motherboard as a rule of thumb????? I might be opening Pandora’s Box with this question.

I have an 850 watts power supply so that does not fit in to the equation.

I do not think that these two fans draw enough current to cause a voltage drop on the motherboard. I do not think these fans inject noise on to the motherboard.

I can buy a multi-port adapter to power the four fans in the case but I am looking to be neat and maybe a tad lazy.
a b V Motherboard
September 14, 2010 5:35:23 AM

Best thing to do would be to get a simple fan controller to take them and power distribution out of the equation entirely. Aside from that, your right not much draw , nor any noise to the motherboard.
a c 112 V Motherboard
September 14, 2010 5:08:11 PM

Power all your case fans of your psu with the 4pin molex connectors.
There is absolutely no reason to use mobo fan headers for case fans.
The only fan you need to power off your mobo is the cooler on the cpu-fan header.
a b V Motherboard
September 14, 2010 7:59:18 PM

I only attach fans to the motherboard that I want to monitor. That is, CPU fan, chipset fan (if I had to add it), HDD-cage fan, the fan-pulse signal from my PSU, etc... Of course, if you can't monitor all those ports, than the point is moot.

I'm not sure why mobo manufacturers started putting extra fan power ports on their boards, but back in the day, if you wanted extra fans, they were powered directly from your supply. Just cause the ports are on the board doesn't mean you have to use them.

Still, it probably doesn't hurt to use them either, so I don't really see any reason not to just do what you want to do.
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