CPU fan stops spinning

Hallo,

I have a problem with my CPU fan. When I turn on my computer, the CPU fan starts spinning (rather slow) for about 5 seconds and then slowly stops. I have to turn on/off the computer a couple of times to get it working but then the CPU fan is working fine for the rest of the session.

Is this a motherboard issue or is there something wrong with the fan?

What could cause such a problem?

Board: Asus A8N-SLI Deluxe
CPU: Athlon 64 - 3200 boxed

It sounds like your fan has crapped out. Does your computer still run when the fan goes off? I wouldn't recommened keeping it on with the busted fan, because it might heat up.

I recently had a similar problem. My fan got louder and louder for about a week, so I just replaced it. Replacement is easy, it just plugs into your mother board. I suggest getting a new fan.

Yes, the computer is still running when the fan goes off. There is another strange thing: I should get a BIOS warning, when the fan is spinning too slow. But I do not get this warning when the fan stops spinning which makes me think that maybe some sensor detecting the fan speed is not working - but I am not sure.

Dont worry, this used to happen on my old Intel 3.6Ghz , it was the old socket, 478. The fan would just turn off, at first i thought it was my power supply because these Intel heatsinks take alot of electricity and the fan does aswell, i heard they can take up to 40% of your PSU under load. Anyway, my fans used to be like yours, but i had no money to buy a new fan so i just left it and you know what, after about 10 seconds the fan will turn on again!, atleast mine did, so yeah, i wish i still had that Cpu, it died like real early for some reason, and then i bought a new fan just to make sure, and yep, it was dead. I dunno why

Unfortunately mine doesn't. If I let the computer on for about a minute and then reset (or power down and then on again) the fan is working. It seems to me as if the CPU has to reach a certain temperature to get the fan going but it does not start until I reset the computer. I have also deactivated Cool & Quiet in the BIOS to make sure that there is no problem there. The fan is silent and does not make any strange sounds.

The CPU fan and fan speed is controlled by the BIOS/motherboard, right? Is it possible then, that this is a motherboard issue and not a fan issue?

P.S. I have noticed that the fan stops for the first time a couple of days after a BIOS update from version 1002 to 1004. Meanwhile I have updated to 1006 but that did not change anything. Could the BIOS update be the source of the problem?

Sorry, now on a more serious note, go into BIOS and if you see a "smart fan control" tab or something that seems like it controls the cpu fan speeds depending on the cpu temperature, make sure it is on disabled, this will make the cpu fan spin at 100% all the time, so if your BIOS is telling your m/b that the cpu is cool, it will spin slow, but fi you have it disabled, itll stay full all the time, hope this helps, post back and tell results.

Hello!

You were right! I have disabled the QFan controller and now the fan is spinning at full speed and does not stop anymore . Plus, with QFan controller on, I have noticed that the fan really starts spinning again after it stops, but this takes some time so I have not noticed this before.

So could this really be a normal behaviour or is there something wrong with the board's temperature controller or a bug in the BIOS ?

I bought an Asus A8N-SLI board a couple of days ago and, as I've been having major problems (not necessarily mobo related), I've been browsing a few forums on the subject.

The general consensus is that Qfan is a bit bugged and you should keep it turned off until you know your system is stable, then try with it turned on and keep an eye on the temperature readouts over a few hours. hth.

So this is a general problem of the board then.
Thank's for your answer.