[wackymacky]

I'm new to macs, and I have had a new imac mid 2007 model (2.4GHz, 20 inch, 1g ram) for aprox one week. For the last two days the fan keeps turning on (located under the left of the screen). This is happening even when there is only one application going, such as fire fox or preview. (ie not system intensive use).

If I put the computer to sleep it winds down, though starts up again often a few minutes of use.
The only software I’ve installed so far is just a new browser (firefox) and MS office 2004.

The fan doesn’t sound 'faulty' though it is about twice as loud as my old PC, and as it is just a few feet away on a desk it is very annoying.

Is this a fault with the computer or normal behaviour?

regards.

[Chinney]

This was an issue on the G5 iMacs. In some cases, I think that this was due to faulty machines or software. In most cases, though, it was simply a reality that the G5s run hot, in a small enclosure, demanding a lot from the fan. Also, unlike the way many people position their PCs, the iMac is inevitably directly in front of you, so fan noise becomes more apparent. Also, unlike many PCs, the iMac seems to have highly-variable fan speed, which somehow makes fan noise more apparent, as it spins up and down. In any case, the problem seems to have diminished somewhat with subsequent updates to OS X, with the random fan spinning largely a thing of the past. There are still some particular apps though – mostly video-intensive apps – that really make my iMac G5 spin its fan.

Moving on to your issue, I had thought that the fan problem had been resolved since the switch to Intel. The Intel chips run cooler, or so I thought. I know that the fan noise on my second computer – a 2006 Intel Mini – is non-existent. My guess is that you have a defective machine or something is not right in your software. Maybe others with Intel iMacs will chime in and give you their perspective.

[dmegatool]

Could it be a some blocked vent or something ?

It's really unrelated but my Mac Pro was loud as hell. I open it and cleaned it up. Now it's back to normal. The heat sink of my x1900 was totally blocked.

[ghoti]

It's certainly not normal to be loud. I would take into an Apple Store to have them check it (don't open such a new computer, that's what warranty is for). I believe there was a software issue with the very early Intel iMacs that made the vents run almost all the time, but that's ancient history now.

[alcimedes]

If you open activity monitor (in utilities), what does it say is going on? Is there something using the CPU? If so, what and how much?

[julesstoop]

Spotlight indexing, maybe?
Have you transfered a large amount of files over from your previous machine? If so, your iMac might be indexing them. Otoh, this shouldn't take more than a few hours.

[mooty]

FWIW, my new iMac 20" is quiet as a mouse. Never heard the fans yet...

[tsa]

I had the problem that the table my new iMac is on resonated, making a quite loud dark rumbling sound. Maybe you have the same problem. I got some sound damping material from my father that he has underneath his wooden floor. I glued three layers of this stuff on top of each other and put the iMac on it. That got rid of most of the noise.

[wackymacky]

Thanks.

Turns out after running a hardware test that there is a fault if the temp senser controling the fan speed.
The nice people at Apple unfortunatly wont give me a new machine and want to fix it, which 'may take a week or two'. Just great timing with Leopard peering through the gate.

[cheezy_poofs_yeah]

good luck, friend.