noisy fan

The fans or the hard drive of my Imac seems to be making a bit of a noise. Initially my I Mac was totally silent. The Imac is now 3 months old. Is this normal or should an Imac be totally silent.

I have a 24' Imac

Thanks
Antony

As the machine ages, the fans will become noisier. This is a normal part of break-in as the bearings in the fans start to wear.

I will tell you that if your iMac is in an area that tends to be dusty, the fans will become caked with dust which can result in more noise and additional wear. So, keep it clean as best you can and buy a can of compressed air to clean off any accumulated dust on the outside of the machine.

In the istat widgit what does it say your various fan speeds are? And do you regularly dust your machine. Yeah my 17" is a little noisier than when I got it also.

The fan in my Macbook gets pretty loud when the CPU's are being hammered, which usually happens if:

I'm watching something on YouTube (normal, and dies down)
I'm viewing widgets (I think "I Love Lamp" is pretty compute bound, normal)
Screen saver is invoked (iTunes artwork)
iCal decides for some bizzare reason that it needs to launch this daemon called "SyncServe", which appears to do absolutely nothing but chew up every freaking cycle of my dual cores for no apparent reason. I have to go into Activity Monitor and kill the bugger (force quit) then my fans quiet down.

I'd look into something like the last item. Launch Activity Monitor and see if there's something hogging the CPU, thus making your fans go nuts. I'd gather that these new Intel Core 2's are powerful enough that even if you have something maxing out the cpu, you won't notice any slowdown, but you will notice the fan going non-stop.