# cpu fan stops just as xp loads



## arkitekten0 (Jan 25, 2005)

I just finished building a new system, and everything worked fine the first day--windows xp home installed without a hitch, other software ran without a hitch.
The second day (today), I turned the computer on and while it was posting everything was fine. The exact moment windows xp began loading the cpu fan stopped dead. The cpu fan alarm (which I had enabled yesterday in the bios) sounded. After about ten seconds (since I don't know how long I have before the cpu overheats once the fan quits) I turned off power to the computer, and at the moment I turned off the power the cpu fan spun again for a few seconds before shutting down. I went through the exact same thing a second time, so it wasn't just a fluke.

Is it ever normal for the cpu fan to shut down while the computer is loading the OS, and if not, how long can I wait to see if the cpu fan starts up again before I risk overheating the cpu?

Thanks for any help!

Athlon 64 3000+ with stock heatsink and fan
Gigabyte nforce4 m/b
Gigabyte 6600 gt pci express
Antec 350W
Seagate 80gb 7200 rpm hdd
Samsung DVD RW
soundblaster 7.1 live 24 bit sound card


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## johnwill (Sep 26, 2002)

As long as the HS is properly installed, you should have more than 10 seconds. If you're concerned, simply get a fan and let it blow into the case onto the processor area while it boots. The CPU fan may just stop temporarly while the system is booting, depending on the specific MB and fan options. I'd let it get booted up and see if the fan starts again.


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## Sarkast (Sep 12, 2004)

I had the same problem with my old HP. For some odd reason one day the CPU fan started to shut off whenever WinXP loaded - and didnt start back up. The only way to keep it running was to shut off hardware monitoring in the BIOS. Very weird.
Well i turned hardware montoring back on and just connected the CPU fan with a 3-4 pin adapter directly to a molex plug - so it always runs. If you get the right adapter you can also have an extra cable for rpm monitoring that you can plug into the motherboard header where your fan was plugged into previously...

Its basically a 1.99$ fix for a problem that could take you forver to figure out why it happens... i went the 1.99$ route. ;-)


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## arkitekten0 (Jan 25, 2005)

Thanks a lot for the help.

I tried going into the bios (which I was able to do before the cpu fan cut out) and I disabled "Smart Fan Technology." Apparently, the mobo can cut the fan out completely when the processor isn't running hot, and I've read on several other forums that AMD's Cool'n'Quiet Technology also shuts off the fan when it's not needed. With Smart Fan disabled, the CPU fan runs continuously.

This seems odd to me, given the little I know, but my impression has been from other reading that the cpu can get dangerously hot VERY fast. Also, enabling Smart Fan Technology in the bios means that I have to disable the CPU Fan Failure alarm (which doesn't seem desireable) because the alarm goes off whenever the fan stops (as opposed to when it fails). 

So, I can either run my CPU fan all the time, or enable Smart Fan and keep the fan alarm turned off... Odd to have to make the choice, but there it is.


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## toxict3arz (Oct 12, 2004)

haha tat must be very odd to make the choice .. but thnx for the tip i didnt know about this before


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## johnwill (Sep 26, 2002)

An AMD processor will go up in smoke in seconds with no HS. If you have a decent HS installed properly, it would take a lot longer for it to get hot enough to damage it. I suspect the fan control was simply working correctly in this case.


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## Danielski (Feb 14, 2005)

i see these posts a lot in every forum about laptops lol
my toshiba tecra A2 cpu fan stops when ever the H*LL it wants and it dosent over heat it will turn back on when it gets too hot its to save power if u were running the laptop on the battery.
i disabled the alarm feature coz i was goin off constantly.


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## arkitekten0 (Jan 25, 2005)

It's great to learn this stuff. I'm really impressed with the high quality of advice and opinion in this forum, and the lack of flaming.

Thanks, everyone!


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