Heatsink Fan 3 pin, yet mobo is 4 pin

[yoclick]

Hi all,

Got a new motherboard + CPU.

CPU: 3800+ X2 AM2
Mobo: M2NPV-VM


Now the CPU is retail so im using the HSF which came with it. However the connection out of it is the normal 3 pin which you connect to the motherboard. However on the motherboard, the pins to connect the CPU fan has 4 pins? Pin layout being

CPU FAN PWM - CPU FAN IN - CPU FAN PWR - GND

At the moment i've had to connect the HSF to a 3 pin socket on the motherboard (labelled CHA_FAN 1). Im just wondering if this was ok or if i should do something about? When on the CPU pins, i would be able to have a warning if it goes under a set limit of RPM but i havent really investigated what the other advantages are. At the moment i just keep getting errors on bootup in the bios that the CPU fan is either not working or under the set limit of RPM [since there is nothing connected to it]. I can change this but before i do and forget about it, please give me some help! Also the HSF is running 3000RPM constant in the current position.

Thanks

[beachboy]

I have an Abit kn9 mobo with exactly the same 3pin/4pin combination. It confuses lots of people but I had come across this previously on Newegg forums before I built my pc.
To be fair to Abit they do make it quite clear in the mobo user manual that it is perfectly ok to connect the 3 pin cpu cooling fan connector to the 4 pin connector on the motherboard board (in Abit's case this is labelled CPUFAN1).
Do NOT connect to (Abit) SYSFAN1.
The 3 pin connector should only fit one way because of the shape of the plastic end-fitting. Refer to the Asus user manual for confirmation or go online to Asus.
In any event there will be no speed control in the BIOS so the cpu fan will run at full speed.
Good luck.

[yoclick]

Cheers!
The asus manual doesnt really tell you much:

7. Connect the CPU fan cable to the CPU_FAN connector on the motherboard.

*Do not forget to connect the CPU fan connector! Hardware monitoring errors can occur if you fail to plug this connector*

Apparently the CHA_FAN1 + CHA_FAN2 are supported by Q-FAN2 (??) so im presuming you can alter the rates. However 3000rpm seems fine to me constant.

[FInalD]

Apparently the CHA_FAN1 + CHA_FAN2 are supported by Q-FAN2 (??) so im presuming you can alter the rates. However 3000rpm seems fine to me constant.

3000rpm?! jees that'll be noisy!

Having a fan control system is very helpful, if you can lower the rates of your fans you'll like your PC more.

Normally with the connectors you get 4pins, but the 3pin connector can only fit on a certain 3 of them.

FinalD

[yoclick]

Yup would be noisy if i didnt have a prehistoric hard drive installed at the mo which is making soo much noise you wouldnt believe it! However tomorrow i shall be getting a new quieter hard drive and hopefully tame down the speed of the CPU fan a tad.

[beachboy]

yoclick,
CHA_FAN1 is a chassis fan (case fan) connection!!
The 3 pin cpu connector should fit on the 4 pin motherboard connector marked CPU_FAN1.
I assume that the PWR_FAN1 connector is for the psu connector.
Since I am not allowed to submit a URL until I have made 5 posts you will have to go to the Asus site, enter your mobo details and select Manual.

Page 44 of the Asus user manual pdf applies.

[yoclick]

Page 44 is about setting BIOS to default? Also dont worry, its on the 4 pin connection lol. However i cant really see a difference apart from i can now enable Q-FAN but i've heard a few people say it was rubbish? With it on the fan goes 1300rpm with cpu temp at 35degree (chassis open). With Q-Fan off, it goes full pelt of just over 3000rpm, same as when i had it connected into CHA_1 FAN. Cant hear a sound difference tbh, the HD is mega loud! I want to keep this HD though along with a new one im getting tomorrow, just wish there was a way of having it turned off unless im accessing it. Dont suppose you know if thats possible

[beachboy]

yoclick,
I have now done my 5 posts so here is the URL which is page 44 of 102 and 1-32 in the introduction.

http://dlsvr02.asus.com/pub/ASUS/mb/...6_m2npv-vm.pdf

I have also read about Asus's famous Qfan in the forums so I wish you well.