Fan Kicking in a lot

[krennon]

The Fan on my desktop has just recently started kicking in a lot and is very very noisy when it does, and it seems to slow the system down a bit when it does kick in, any ideas why it would be kicking in a lot and what I should do about it?

[spinner]

Assuming you are talking about the chassis fan. Oh and what do you mean by 'kicking in'? They are designed to run continuously. The fan's operation is controlled by heat sensors on the MB. Being noisy while running could be the result of dirt buildup or the fasteners having come loose allowing vibration. I've never heard of a fan slowing a system down. That said, the fan kicking in at the same time the system slows leads me back to a possible overheating situation. When was the last time you opened the case and blew out the dust? It's amazing how much can accumulate inside dependent on the environment. There is software that will tap into the BIOS information and let you know the system temps, or you could boot into the BIOS when the symptoms occur and check the temps directly from the BIOS readings.

If, on the otherhand you are talking about the power supply fan, then likely the power supply is breaking down and your only option is to replace the power supply.

[Mick]

I would have thought if it was slowing things up then it's probably dust in the heatsink, and the fan on the heatsink speeding up.  Is this a AMD processor?  They don't like heat as much as Intel.

Check the obvious air intakes and exits on the case.  And if they are blocked then you might also find quite a build up of crap on the processor heatsink inside.  look through the fan.  You can very carefully remove this with a soft brush and a blow.     

[Alfonso_Frisk]

I downloaded speedfan when my desktop was running  noisy
http://www.almico.com/sfdownload.php

I can control the speeds of the fans without affecting the temperatures too much. for e.g. my motherboard fan now runs very quiet at 60% of normal speed.
A few diagnostics also available with it.
QUOTE
SpeedFan allows you to have a deeper view of the status of your computer. Almost every computer includes support for hardware monitoring. Accessing digital temperature sensors is really useful. If you are trying to figure out why your pc hangs when under heavy load or after some hours of usage, SpeedFan might help you to find the real cause. Very often it is a poor power supply, or an improperly installed heatsink that lead to behaviours that we tend to associate with errors from the operating system, but that are not. SpeedFan automatically searches your computer for interesting chips: the hardware monitor chips. SpeedFan can expose voltages, fan speeds and temperatures. On rare occasions, the BIOS doesn't activate such features. SpeedFan tries to enable them as long as this is a safe thing to do. Not only the motherboard is searched, but also some video cards and almost every recent hard disk. SpeedFan can access status info from EIDE, SATA and even SCSI drives, showing, in a consistent way, internal data that can be used to diagnose current and future hard disk failures. This is known as S.M.A.R.T. (Self-Monitoring Analysis and Reporting Technology). At the lowest level, SpeedFan is a hardware monitor software that can access digital temperature sensors, but its main feature is that it can control fan speeds according to the temperatures inside your pc, thus reducing noise.

[Colin]

More than likely a build up of dust in the case particularly on the cooling fins on the processor. Carefully blow it away and you will probably be back to 'silent running'. If that doesn't fix it then a new fan will probably be called for.

[Hinfrance]

I'm with Colin, probably dust. Stick the vacuum cleaner on low power over the fan exit and loads will come out. You might also want to take the side panel off and give the rest of the insides a clean too.

Your problem is probably not as bad as THESE, but worth cleaning first for sure 

[Oldboy]

A quick balst of air should do the trick. Maplins sell the cans, but make sure the computer is switched off and unpluged first.