Determining Fan Speeds

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Level 7

23,831 points

Determining Fan Speeds

Seeing as how I've now become interested in fan speeds ( see http://discussions.apple.com/message.jspa?messageID=1773575#1773575 ) I looked into how they are read. Many here seemed to be using XRG for that, so I downloaded the newest version of that and have been playing with it for a while this morning.

I can't figure out any way to get fan speeds read out in any way that makes sense. I can graph them in the Temperature graph area, can graph up to three of them, but absent any scale or index I can't figure out what the graphs are representing.

Can anyone possibly shed some light on this? TIA for any inputs or assistance.

iMac G5 17" iSight, Mac OS X (10.4.3)

Posted on Feb 20, 2006 11:11 AM

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Answer 1

Feb 21, 2006 7:36 AM in response to Michael Morgan1

Hardware Monitor is very good for the price. I think it comes out to like 10 bucks. It shows all sensors in the iMac and graphs all of them over time. It was pretty intersting though when you switch the processor speed from automatic to high, how much the processor temp, the fans and the amp goes up. I guess that goes without saying.

At the automatic setting with nothing going on the fans speeds are at 1200 rpm.

I am not sure if you can get the sensor readings from a terminal session. I don't know of a unix command that will give you that. I am not that savy in that area. The only one that I know is TOP. Which will give you the processor usage and process etc.

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Answer 2

Feb 20, 2006 3:12 PM in response to Michael Morgan1

Michael,

Using Hardware Monitor will tell you everything about your iMac including the fan speeds. Below is the output from the app. Is this what you are looking for? The site for the app is http://www.bresink.com/osx/HardwareMonitor.html.

107.3℉/ 41.8℃
CPU Temperature

150.1℉/ 65.6℃
Graphics Processor Ambient Air

163.6℉/ 73.1℃
Graphics Processor Temperature

111.2℉/ 44.0℃
Hard Disk Temperature

81.5℉/ 27.5℃
Incoming Air Temperature

129.2℉/ 54.0℃
Memory Controller Ambient Air

162.9℉/ 72.8℃
Memory Controller Temperature

99.5℉/ 37.5℃
Optical Drive Temperature

114.8℉/ 46.0℃
SMART Disk WDC WD1600JS-40MVB1 (WD-WMAP01035274)

12.16 V
CPU 12 V Supply

0.70 A
CPU 12 V Current

1200 RPM
CPU Fan

1200 RPM
Hard Drive Fan

1000 RPM
Optical Drive Fan

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Answer 3

Michael Morgan1 Author

Level 7

23,831 points

Feb 20, 2006 3:27 PM in response to TempusThales

TT,

Thanks for the steer, it's a very nice looking utility program. I've just grabbed and installed the demo version which, of course, doesn't included the fan speeds. It may well be worth the few €s that they are asking.

I already have a nice little widget running which does pretty much everything except fan speeds already, and I'm not sure how important the actual speed values are. I already know what normal sounds like, and maximum.

I've got to assume that all of this system info is otherwise available, perhaps through Terminal or some such? It might be interesting to just find that out somehow.

M.

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Answer 4

Bruno.

Level 1

133 points

Feb 27, 2006 7:25 PM in response to TempusThales

You can monitor internal sensors temperature and fans speed using a terminal session. The command is ioreg. "ioreg -w 0 -S -n IOHWSensor" will give you details on temperature sensors and "ioreg -w 0 -S -n IOHWControl" will give you details on fans speed. You can filter the results by adding « |grep "{\|\>" » (without the «»). This will give you only the lines containing a { or a ". One thing, the "current-value" field of temperature sensors is not expressed in degrees, and I have not tried so far to convert the value to degrees.

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Answer 5

Michael Morgan1 Author

Level 7

23,831 points

Feb 27, 2006 8:04 PM in response to Bruno.

Thanks, Bruno ..... I figured these data points had to be (fairly) easily acccessible what with all of the little widgets and utilities out there that report their values out.

I've clipped out the two strings for use in Terminal whenever I next work up the courage to go in there and play around. No sense depending on typing skills ...

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