How to tell if a fan is working properly?

cpetaling

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Apr 19, 2007
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Hi,

I have my casing open for some time, and I used to wonder if the noise the CPU fan was making is really louder than it is supposed to be. It is a loud even hum, which doesn't cause the case to vibrate but you could easily tell that the PC's on from several meters away.

I have a P4 3.0 CPU and a ASUS P4P800 motherboard. I do recall once having to remove an extra optical drive because the CPU fan refused to work with two HDDs and two DVD-ROM drives.

Also, I have noticed at times when I run ASUS Probe that it occasionally warns me that a fan (either the CPU or chassis) has negative RPM ("CPU fan below threshold!"), which is strange because I can clearly see both sets of fans spinning (in the same manner as described above) from where I sit.

The same ASUS Probe software currently reports my CPU and Motherboard temps at 31 and 46 degrees celsius, respectively.

Does it look like I need to do something with the fan :?:
 
Your temperatures are fine. The fan in red is spinning slowly. If it is a slow speed fan you can disable the warning in the Bios if you like, but it could be a sign of a dying fan also if it is a regular fan.
 

rammedstein

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Jun 5, 2006
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nope, i wouldn't, the rpm with is a modulated pulse, so if the fan skips a beat your computer goes wtf and says it has negative rpm, doesn't matter though because on the next cycle it will pick up again.
 

cpetaling

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Apr 19, 2007
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just what i thought. you're right, the monitor does pick up the correct rate after a few seconds; but admittedly the no cpu alarm is quite distracting.