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Two case fans; which one should have system control?

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June 21, 2012 3:59:37 AM

Hello,

This is an issue that has irritating me lately. I have built my own computer from parts and I am unsure how to connect my case fans. In my computer case, I have installed two case fans: one one the side panel blowing air into the system (onto the graphics card), and another on the back of the computer, blowing air out. However, my motherboard only has one system-controlled three-pin connector on it. Therefore, only one fan can be connected to the other board, and the other fan must be connected directly to the power supply via the included adapter (or I can have both connected directly to the power supply).

So my question is, does it matter which fan is system controlled and which one isn't? I'm not sure whether the side intake fan should be system-controlled so that the rear fan always blows hot air out at maximum RPM. Or, have the rear output fan system-controlled so I always have maximum RPM blowing cool air into my system. (Or have neither system-controlled, having both fans at max RPM all the time) Noise is not an issue for me. What is the general consensus on this issue? Thanks for your advice!



One more thing... I can install my side case intake fan in two positions: low (over the graphics card) or high (over the processor, which is already fan cooled). The rear fan is high up in the case, so I suppose it makes more sense to have the side fan lower down in the case to allow air to flow through the entire system, therefore I installed the side fan in the low position. Do I have this correct? Please tell me if I should have it the other way around.

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a c 87 ) Power supply
June 21, 2012 4:36:12 AM

Welcome to Tom's Hardware Forums!

Yes, you have it correct! Rear fan direct to the PSU; full speed for max air exhaust. Side fan blowing air on the Graphics card will work fine. Ant that too, you can directly connect to the PSU.
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a b ) Power supply
June 21, 2012 4:55:32 AM

jackpotting said:
Noise is not an issue for me.

Then connect the fans direct to the PSU. More airflow is pretty much always better when noise isn't an issue. And definitely put the side fan over the graphics card.

Using the motherboard's system fan connector is not necessary as long as you are still providing airflow from somewhere.
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a b ) Power supply
June 21, 2012 4:59:54 AM

Doesn't matter which you plug into what.
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June 29, 2012 4:59:48 AM

Great! Thanks everyone for your advice; I have both fans connected to the PSU, and even with the fans at full RPM it is not very loud, not loud enough to cover up the hard drive read/write noise. Now I'll never worry about my computer overheating, even though it never really gets hot anyway.
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July 5, 2012 11:55:22 PM

Best answer selected by jackpotting.
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a c 87 ) Power supply
July 6, 2012 10:24:07 AM

Thank you!
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