Snow Leopard, iMac Temperature and Fans?

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Level 7

24,242 points

Snow Leopard, iMac Temperature and Fans?

Since getting my iMac eighteen months ago I have checked the temperatures regularly.

Unfortunately I did not write them down and cannot remember what the highest "normal" temperature was, though the hottest place was always the "Power Supply Position 1".

One thing I am certain of is that I thought the 3 fans just had one set speed because every time I checked the Optical Drive was always around 699rpm and the HD and CPU fans were always 1199rpm.

Until a couple of weeks ago I had not updated the original OS which was 10.5.2, but then I updated to 10.5.8 in one go and last week I upgraded to Snow Leopard 10.6.1 by installing it over Leopard.

Today I was doing some simple editing in Final Cut Pro for an hour and checked the temperature.

The Power Supply Position 1 was 176 degrees F. I can't be sure but I have a feeling that I have never seen it above 169.

I then put a 20 minute video in Compressor to encode and the temperature rose to a maximum of 179.6 and the CPU fan was around 1500rpm which I have never seen before.

Has SL had any effect on temperatures or fan speeds?

Are these figures normal?

My room was only 66 degrees which is fairly cool.

24" 2.8 GHz (Penryn) 4GB RAM iMac, Mac OS X (10.6.1), Iomega 1TB USB 2.0 HD + LaCie Quadra 500GB HD

Posted on Nov 9, 2009 11:59 AM

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Answer 1

K T

Level 7

23,889 points

Nov 9, 2009 12:04 PM in response to Ian R. Brown

Has SL had any effect on temperatures or fan speeds?

In my case, I was using SMB Fan Control & Temperature Monitor before SL to settle down an overhearing machine. SL makes those obsolete now for me...all is well without them.

Do the basics...be sure there aren't any dust bunny colonies blocking vents, heat sinks, fans etc.

If you need them, to those two apps will let you DIY fan control.

Good luck in any case.

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Answer 2

Pondini

Level 8

38,863 points

Nov 9, 2009 4:06 PM in response to Ian R. Brown

You might also be interested in the +Hardware Monitor+ App, from: http://www.bresink.com/osx/HardwareMonitor.html

It keeps a week's worth of readings from temperature sensors, fan speeds, power use, and you can add "probes" for things like CPU utilization, etc.

You can have it show a reading in the menubar, one or two in the app icon in the Dock, and a whole bunch of customizable graph windows. Click "Screenshots" and scroll down.

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Answer 3

lkrupp

Level 7

22,633 points

Nov 9, 2009 4:19 PM in response to Ian R. Brown

I'm running OS X 10.6.2 (was OS X 10.6.1) on a 24" iMac8,1. My fan speeds are at the usual minimum (CPU fan 1199, hard drive fan 1199,Fan Optical Disk Drive 699) and my Power Supply Position 1 is 176.0°F as it has always been in the past. So, from my perspective, Snow Leopard has not affected my iMac in any negative way.

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Answer 4

Ian R. Brown Author

Level 7

24,242 points

Nov 10, 2009 12:28 AM in response to lkrupp

Thanks K T and Pondini.

That's really what I was looking for Ikrupp, some figures from other users under moderately intensive operations (not writing emails!).

Yesterday, when I had finished using Compressor the temperature started dropping from almost 180°F and when it reached 176°F the fan had also dropped to 1199rpm so it looks as though it doesn't speed up until the temperature exceeds 176°F.

It appears that your figures are pretty close to mine. However, if others could give me figures they get under moderately intensive use, it would give me final confirmation that all is well (or not).

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Answer 5

Ian R. Brown Author

Level 7

24,242 points

Nov 10, 2009 12:46 AM in response to Pondini

Just downloaded Hardware Monitor and discovered that it is a more advanced version of Temperature Monitor that I have been using for several years.

What I did not know was that both apps will record the temperatures in the History setting.

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