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Computer seems to turn fan on fast.

  1. May 6, 2009 #1
    Hi everyone,

    My computer fan keeps turning on fast, and then turning off (I think it's the fan, I'm not sure). The computer didn't seem to do that before. I was wondering if this is a bad sign (overheating?), and what should I check?

  2. jcsd
  3. May 6, 2009 #2


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    Vacuum all the dust bunnies out of the computer and fan.
    It might also be that the thermal contact between the CPU and heatsink+fan is poor because it has been knocked loose or the contact grease has dried out
    Get a utility that monitors the CPU temperature.
  4. May 6, 2009 #3


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    Some video cards also have fans, so check that as well.
  5. May 6, 2009 #4
    Does your system also slow down around the time (or slightly before) the fans speeds up? I've had this happen on Windows systems that are running lot of background processes (e.g. antivirus or spyware sweeping programs). You think the computer is just sitting there at rest, but then it turns out that the CPU is maxed out running these processes you couldn't even see (and getting very hot as it does it).
  6. May 6, 2009 #5
    This happened to me a few years ago. The cpu fan would turn on high speed for no apparent reason (cpu usage was very low). When I opened the box and looked at the cpu, I noticed that one of the bands that hold the heat sink to the cpu had snapped off. So you might want to check that.
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