iMac 2.16GHz fans, speeds and temp

Got a new iMac for Xmas! 20in Core 2 Duo 2.16GHz model. I love everything about it.

When I first got it, the fans made a low rumbling sound. I could live with this. It was like hearing the noise of an air-con unit through a wall. Quiet, almost soothing.

Over the past week, the noise the iMac makes has got more whiney. Thinner, with higher pitch elements. I like a quiet office and it's really annoying.

On other forums, I've checked with others about fan speeds, and it seems I match theirs (Fan 2: 830, Fan 1: 1400, Fan 0: 799; all details from iStat).

I've removed the screen-buzz issue from the equation. That doesn't appear to affect me. I've reinstalled OS X. I've reset the PRAM. It hasn't gone away.

This morning I downloaded CoreDuoTemp (http://macbricol.free.fr/coreduotemp/). This is reporting that the minimum speed my processor can reach is 1GHz, and the maximum 2.17GHz. BUT!! The current speed is 2.17GHz. It never changes, even when my PC is idle.

I was under the impression that Core 2 Duo chips are supposed to manage their speed dynamically, for power saving, stepping down when idle...?

Is it possible my iMac has got "stuck" at max speed, somehow?

Any help appreciated.

What are your CPU temps?

Alexis said:

What are your CPU temps?

Click to expand...

Right now I'm just browsing the web. Here are the figures from iStat Pro.

CPU A: 40 degrees C
GPU Diode: 49 degrees C
Ambient: 29 degrees C
Optical Driver: 39 degrees C
Drive Bay 1: 40 degrees C

CPU load is averaging around 5% as I type this. Fans are roughly the same as those quoted earlier.

I've had mine replaced because of a few issues.

1) The fan got high pitched and annoyed the heck out of me.
2) The Tech told me that the CPU's should be opperating at around 65 degrees C but they were at only 15.
3) The backlight was uneven


Maybe you should ask Apple to take a look at it.

és: said:

I've had mine replaced because of a few issues.

1) The fan got high pitched and annoyed the heck out of me.
2) The Tech told me that the CPU's should be opperating at around 65 degrees C but they were at only 15.
3) The backlight was uneven


Maybe you should ask Apple to take a look at it.

Click to expand...

I think I've figured this out. It's the hard disk. I know this because, when it spins down, the sound goes. I'm left with the gentle whirr of the fans. Then, when I click on something, I can hear the drive spin up and the sound returns.

I'm not sure Apple will take me seriously if I took it in for repair. The drive works, and SMART checks out OK. I've just got a particularly noisy rendition of the ST3250824AS Q hard drive that Apple fit to 20in iMacs

I suspect buying a replacement and manually fitting it is the only way to go. At the moment the noise is driving me mad.

I've got the noisey HD myself, complete pain. I will be glad when my new machine arrives.

és: said:

I've got the noisey HD myself, complete pain. I will be glad when my new machine arrives.

Click to expand...

Did you try taking it in for repair? I'm going to give Apple a call tomorrow and see what they say.

és: said:

I've got the noisey HD myself, complete pain. I will be glad when my new machine arrives.

Click to expand...

Mine is very noisy on startup for about 15 min, it is a iMac G5 though, do you think apple will replace it? I even have applecare...

r-sparks said:

Did you try taking it in for repair? I'm going to give Apple a call tomorrow and see what they say.

Click to expand...

My advice is when you call Apple make sure you put as much emphasis on how much of a royal pain in the proverbial it is to you and how much it ruins your Mac experience so to speak. You have paid a lot of money for your Mac and deserve to have a product which works for you - not the other way around. Excersise your consumer rights and don't be put off by anyone, demand it be fixed yesterday... I know, I've been there, done that and boy did I have to fight hard to have my iMac G5 replaced.

r-sparks said:

Did you try taking it in for repair? I'm going to give Apple a call tomorrow and see what they say.

Click to expand...

Well, it was a complicated situation. I sent it in for all of the things mentioned and they had a delay in getting parts so I asked for a new machine. Apple kindly agreed and I am waiting for hte new machine to be delivered.

I would take yours in and say that it really bugs you. You might have to buy a new one at some point, but if you are lucky then you might get one for free. Worth a shot, I guess.

There's a constant hum in the office from 2 printers, so the iMacs sound silent.

The fan did boot up for around 2 minutes yesterday though, which is the first time I've heard it be loud since I got it.

My CPU temp is usually around 40C.

I recieved my new machine today.

HD = A lot quieter
Fan = A lot quieter
Screen = About the same
Speed = A lot less sluggish

All in all very happy with my new machine in comparision.