Fan noise on 24" aluminum iMac?

docprego

macrumors 65816
Original poster
Jun 12, 2007
1,201
61
Henderson, NV
I just picked up a new 24" aluminum iMac, it is absolutely beautiful. This is not the 1st 24" i have had, I had another in late August. I noticed a few differences that I was wondering about.

First this one seems to have a fan running most of the time, it is a very quiet fan but it is audible. I seem to remember my other 24" making no noise at all. Second the DVD drive makes a lot more racket when being fed a disc. Third the OS boots to the desktop in about 10 seconds, it is lightning fast!

Please keep in mind that I installed Leopard on this computer yesterday. If this fan noise is typical of the latest iMac hardware I'll stop obsessing over it. Has anyone else bought a 24" in the last few days that exhibits this behavior?

I did a SMC reset and that seemed to help a bit but I can't really remember what the noise was like prior to the reset so it might not have done anything.
 

docprego

macrumors 65816
Original poster
Jun 12, 2007
1,201
61
Henderson, NV
What happened to your first iMac (alu, I assume)?
Long story.....

Right now my iMac is VERY quiet just a whisper of fan noise. Temperature is 42 degrees and these are my fan speeds:

ODD 699
HDD 1200
CPU 1199

The weird thing is that these fan speeds were essentially the same earlier when the machine was a lot noisier. I put it to sleep, came back 5 minutes later and now it is very quiet but all the fan data seems the same. I think the temperature was a bit higher before sleep though, 45 if I remember correctly.
 

je1ani

macrumors 6502
Sep 19, 2007
455
1
yeah everything you've listed above is I think pretty normal as it's the same for my machine... my only hang up is that it gets pretty hot on the top.. even when surfing the web..
 

docprego

macrumors 65816
Original poster
Jun 12, 2007
1,201
61
Henderson, NV
yeah everything you've listed above is I think pretty normal as it's the same for my machine... my only hang up is that it gets pretty hot on the top.. even when surfing the web..
Thanks but does your fan noise increase after the machine has been on a while? It is still not a very noisy fan but it is audible compared to the almost complete silence of when it first is turned on. All aluminum iMacs I have felt get hot on the top, that is normal too.
 

ahoegh

macrumors newbie
Sep 23, 2007
28
0
It seems to me that the 700/1200/1200 rpm is the same all the time, no matter what the iMac does. Anyway, I've not seen it change.

My iMac seem a little louder when I come down here after having left it doing something for a whole night, even though it isn't doing something that requires CPU power. It could be my imagination, but i've noticed it again and again.
 

docprego

macrumors 65816
Original poster
Jun 12, 2007
1,201
61
Henderson, NV
I figured it out. When the screen is at certain angles there is a buzzing sound that is produced. It is sort of a reverberation, but if I move the screen to a different angle it totally disappears. I was mistaking this for fan noise. It reminds me of my Optoma HD70 projector which I sent in for a similar annoying buzz. That turned out to be a fan bearing. I wonder if this is something similar. I hate to send it for service and I dread returning it as the screen is PERFECT. What would you do?
 

docprego

macrumors 65816
Original poster
Jun 12, 2007
1,201
61
Henderson, NV
I have new discovered that the buzz is coming from the plastic rear casing. I can make it go away by placing a finger on the black plastic casing just behind the Superdrive slot. It takes hardly no pressure at all to eliminate the buzz. I am very annoyed and disappointed by this flaw.
 

docprego

macrumors 65816
Original poster
Jun 12, 2007
1,201
61
Henderson, NV
Exchanged it today and all is well. Now that I hear how it is supposed to sound, I realize just how noisy that one was. Very pleased with the new one.

BTW Leopard is phenomenal, I absolutely love it. It feels very familiar yet very new at the same time.
 
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