Fan power splitter causes persistent fluctuation of one fan

Aidan P

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Sep 20, 2013
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My motherboard (an ASUS P8H61-MX R2.0) has just one case fan power port. Quite some time ago I purchased a Corsair Air Series AF120-LED 120mm fan, and later purchased a second to mount at the front of my case to act as an intake, and therefore I needed a power splitter to power both. They work fine, however for some reason, when the front fan is powered, it persistently fluctuates its RPM and is very noticeable in regards to noise. Otherwise, my PC is very quiet and the rear fan (even when plugged in to the splitter) does not do this noticeably.

As a result, I leave the front fan unplugged however I'd like to use it if I could solve the issue.
 
Solution
The motherboard is not designed to power 2 case fans. If it were, there would have been two headers. You may damage your motherboard by attempting to draw too much current through that one header when you use a splitter. I suspect what you are seeing with the 2nd fan fluctuation is the power circuit limiting itself so as not to self destruct.

Power the second case fan from an unused disk drive power connector. If you want control for that second fan use a fan controller hub.
The motherboard is not designed to power 2 case fans. If it were, there would have been two headers. You may damage your motherboard by attempting to draw too much current through that one header when you use a splitter. I suspect what you are seeing with the 2nd fan fluctuation is the power circuit limiting itself so as not to self destruct.

Power the second case fan from an unused disk drive power connector. If you want control for that second fan use a fan controller hub.
 
Solution