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Help connecting PSU/MOBO/COOLER/FANS

Last response: in Overclocking
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March 21, 2010 7:27:22 PM

Hi all,

I'm a first time builder who has bought all the components for a new PC and would appreciate some help wiring the fans up. I have:
- Lian Li PC-B25F case. This has 5 fans ...
* 2 x 120mm (1200 RPM) fans on the front panel
* 2 x 140mm (1000 RPM) fans on top of case
* 1 x 120mm (1500 RPM) fan on (upper) rear panel of case
* PSU is mounted on (lower) rear panel of case

- P7P55D-E pro motherboard
- Noctua NH-D14 (comes with 2 x radiator fans)
- i5-750
- Seasonic X-650 PSU

(I also have other components RAM, Video card etc too).

My motherboard has the following fan headers:
- CPU_FAN (middle of the board)
- CHA_FAN1 (adjacent to CPU_FAN)
- CHA_FAN2 (extreme bottom right corner of board)
- PWR_FAN

I was wondering what the best way connect all of the available fans to my Motherboard would be (which should be connected to the motherboard and which to the PSU)? I have a y-splitter cable so that I can wire both of my Noctua coolers fans to a single fan header. Will my motherboard be able to power these OK? (The fans look huge). Also, the motherboard has Asus's Fan Xpert technology built in so I'd like to make sure everything's connected to use this if possible!

Thanks in advance all!
a b V Motherboard
a b K Overclocking
March 21, 2010 9:37:17 PM

I do not recommend using the y splitter cable to connect the two cpu heatsink fans to the cpu_fan connection on the motherboard. It can cause problems.

1. Connect one cpu heatsink fan to the cpu-fan connection on the motherboard. The is mandatory so the system can monitor the fan. If you go into BIOS when you start your computer you can make adjustments to the fan speed or let the system control the fan speed based on cpu temperature. Your system may also be able to control additional fans connected to the motherboard. It just depends.

1. Connect a second cpu heatsink fan to another connection on the motherboard, probably the cha_fan1 since it is adjacent to the cpu_fan connection.

3. Connect the fan on the rear panel of the case to another connection on the motherboard.

4. Connect one of the case fans to the last available connection on the motherboard. Just select a fan that conveniently located near the connection.

5. You can use y splitters and adapters to daisy chain the remaining fans and connect them via one connection to the psu.

pwr_fan - A long long time ago in a galaxy far far away there used to be power supplies with an external fan cable that could be connected to the pwr_fan connection on the motherboard. The system would control the speed of of the power supply fan based on the cpu temperature. I haven't seen one of those psu's in a very long time. They are pretty much obsolete. It is perfectly okay to connect a case fan to that connection on the motherboard.

May the Force be with you! :D 
a b V Motherboard
a c 78 K Overclocking
March 22, 2010 7:00:48 AM

If your case fans have a 4pin male molex connector then their best connected in series to the PSU.

Each header for the fans are PWM (something Pulse generator :D  ) so its not wise to use a splitter cable on ANY 1 of those headers and also because the board monitors each fan individually.

I know the Noctua's come with a U.L.N adapter (you can use that by attaching them before connecting the main pins to the mobo) make sure you have 1 connected to the CPU_FAN1 and the 2nd CPU fan can go into the CHA_FAN1(or the one thats closest). CHA_FAN2 seems to be capable of hooking up with a case fan in front of your case. While you use the PWR_FAN connectors to hook up the case fan at the back of your case (provided it has the pins that go to the mobo)

@Johnnylucky - haha starwars - wonder if they'll come back with a sequel?
!