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10.5: More control of fan speeds on iMacs and laptops Apps
We take great care to ensure that our systems run with reasonable temperatures as that helps extend their lifetimes. We've used various applications to control the fan speeds on different systems but, with the upgrade to 10.5, our Intel-based iMac was left without a fan-control solution that worked adequately. To that end, I decided to modify the open source (GPL) FanControl to work with our iMac. The result is that I've generated two new versions of Fan Control, one for the Intel-based iMacs and one for the MacBook/MacBook Pro.

These versions also have some extended control capabilities over the original FanControl. The iMac version uses separate sensors to drive the control of each of its three fans. The MacBook/MacBook Pro version allows use of the CPU and/or GPU temperatures to drive the fans. (The GPU-based operation can be useful if you play games.) There are some other minor enhancements, noted in the Read Me file.

I've also tried to make it easy for anyone who might want to modify the source code and adapt it to other systems ... e.g., to generate a version for the Mac Pro that uses different sensors to control different fans (or groups of fans). Hope this is useful to others.

[robg adds: I tested the MacBook Pro version, and it worked well. Another open-source fan control option is smcFanControl, a previous Pick of the Week selection.]
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10.5: More control of fan speeds on iMacs and laptops
Authored by: swimboy1 on Jul 17, '08 08:18:19AM

Having control of the fans is all well and good but what should I be setting the values too? My iMac seems to get very hot.

Any guidance on the upper temps, fan speeds etc would be welcome.

Richard



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 12:34:45AM
Settings will vary depending upon your environment and system usage patterns. The current settings on our iMac are:
- Lower Temp Threshold : 90F/38C
- Upper Temp Threshold : 160F/82C
- Slowest CPU Fan Speed : 1600
- Slowest HD Fan Speed : 2200
- Slowest DVD Fan Speed : 1000

The current settings on my MacBook Pro 2.33 Core 2 Duo are:
- Lower Temp Threshold : 100F/32C
- Upper Temp Threshold : 180F/71C
- Slowest Left Fan Speed : 1300
- Slowest Right Fan Speed : 1300
- controlled by: CPU for both

With these settings, the HD in our iMac stays below 110F/43.3C (other temps were not an issue and stay similarly low). The temps on my MacBook Pro normally sit with the CPU (diode) sensor at around 120F/48.9C, increase to around 140F/60C when moderately taxed and have seldom exceeded 170F/76.7C. Though I do regularly run tasks that tax both these systems (i.e., keep both processors sitting at 50-70% usage for tens of minutes), I don't do anything that stresses the GPU on either of them.

BTW, if you want to track temperatures, I've found Hardware Monitor to be an excellent application.

Raising the Lower Temp Threshold will control/raise the temperature at which Fan Control begins to increase the fan speeds (based upon the current temperature from the applicable sensor[s]).

Decreasing the Upper Temp Threshold will control/lower the temperature at which Fan Control increases the fan speeds to their maximum (based upon the current temperature from the applicable sensor[s]).

Note that the steeper the slope of the graph's "control" line, the more rapidly fan speeds will be increased as temperatures rise (and vice versa).

While I'm no expert on the subject and/or the components used in any of the Macs ('though I do have an electronics background), my decisions are based upon the following:

- while doing basic browsing, email reading, etc. (i.e. light usage), I wouldn't want any fan to be running at any more than 1/2 of its maximum speed and, ideally, only at about 1/3 of it's maximum speed

- I'd much rather run the fan at a higher speed than suffer high temperatures (the ol' "rule of thumb" in electronics was -- and I'm going way back here! -- for every 10 degrees Celsius rise in temperature [above 20 degrees Celsius], you half the life of the semiconductor)

- my understanding is that hard disk temperatures should be kept below 113F/45C

- I strive to keep chips (CPU, GPU, Airport Card, etc.) always below 158F/70C except in sustained/peak-usage situations and around 131F/55C in moderate use

Hope this helps, a little

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10.5: More control of fan speeds on iMacs and laptops
Authored by: swimboy1 on Jul 18, '08 10:21:27AM

Many thanks for your excellent advice and feedback.
I'll tweak my settings and try to take note of the overall effects.
Thanks again, Richard



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10.5: More control of fan speeds on iMacs and laptops
Authored by: ddauerbach on Jul 18, '08 11:09:42AM

That's great, it works fine BUT should I follow your suggested farenheit profile or the centigrade one. (They aren't the same, you know.)



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 11:46:35AM

Oops! #;-}
[that's a somewhat fuzzy-headed red-faced, sheepish grin]

Sorry, for temperatures I still prefer to think in Fahrenheit ('though, officially, Canada is metric) and, when I was adding the Celsius equivalents, it appears that I put them on the wrong set (i.e., the MacBook's Celsius temps should be on the iMac and vice versa).

Short story, the settings I've arrived at are the Fahrenheit ones.

In reality, you should try some initial settings, watch what happens with your own usage patterns, and adjust as necessary. There's enough flexibility in the settings that it should do a very good job for nearly all usage patterns.



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10.5: More control of fan speeds on iMacs and laptops
Authored by: Ocid on Jul 17, '08 08:28:14AM

I downloaded the MacBook & MacBook Pro version but the GPU temp shows only 0.0 degrees. I have Apple MacBook Pro "Core 2 Duo" 2.4 17-Inch (Santa Rosa)



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 12:40:53AM

If all the readings in the panel show zero and/or non-changing values, it's likely that the FanControlDaemon (see /Library/StartupItems) is not running.

If it's only the GPU temp, then it's likely that the code to read the GPU temp is different in your model. You could look at the source code stuff and try to figure out what the code is (there are some tools included that may help). If you can determine the code, just change it in the .h, recompile and you'll have a version that works. Of course, this does assume that you have a bit of software development background. If you do that, don't forget to post the information so others can benefit.



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10.5: More control of fan speeds on iMacs and laptops
Authored by: Graeme_Smith on Jul 17, '08 10:14:49AM

So can machines actually get ruined due to running to hot? Is this an issue one should actually worry about? I've noticed my iMac (aluminum) gets very hot on top but I assumed they were meant to run that way and that Apple had everything under control...



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 12:47:01AM
Yes. All other things being equal, the hotter a system and its components run, the short its life. While this is not a practical concern at some temperatures, modern-day systems are quite capable of generating enough heat to significantly shorten their lives. See another reply for additional comments.

Personally, I think that something like Fan Control should be part of Mac OS X.

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10.5: More control of fan speeds on iMacs and laptops
Authored by: ascanio on Jul 18, '08 02:36:01AM

BTW, on my old PowerBook G4 the excessive heat fried the optical drive connector (it couldn't write DVDs anymore) and the firewire ports. On the new MacBook Pro I always try to keep the temperature as low as possible (reasonably)



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 11:49:21AM

Re: ...the excessive heat fried the optical drive connector...
---
Ouch! Must have been "one hot movie" you were watching! <sic>



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10.5: More control of fan speeds on iMacs and laptops
Authored by: mankoff on Jul 17, '08 12:55:00PM

Are you sure FanControl didn't support Intel? I installed it yesterday on a MacBook and PowerMac Intel and it seemed to work fine...

---
http://pace.edgcm.columbia.edu



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 12:49:14AM

Fan Control only runs on Intel-based Macs ... and only under OS X, not under Windows/Bootcamp/etc.



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10.5: More control of fan speeds on iMacs and laptops
Authored by: zyxkenadams on Jul 17, '08 08:33:48PM

i just downloaded this, but it shows all temperature values as 0.0 degrees! how do i completely get rid of this and set the speeds back to normal, because now they are at like 3500+ rpm



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 18, '08 01:01:03AM
I think smcFanControl has an option to reset things to the default settings.

Alternatively, search Apple's support site for information on resetting the PMU (power management unit) and/or SMC (system management controller) for your system/model.

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10.5: More control of fan speeds on iMacs and laptops
Authored by: swimboy1 on Jul 18, '08 10:19:39AM

Many thanks for your excellent advice and feedback.

I'll tweak my settings and try to take note of the overall effects.

Thanks again,
Richard



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10.5: More control of fan speeds on iMacs and laptops
Authored by: stroh on Jul 19, '08 01:54:19PM

Just curious, but are there any warranty issues that come up when using something like this?



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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Jul 20, '08 12:34:37AM

Yeah, if your systems run at cooler temperatures, you'll be much less likely to require any warranty repairs (unless you got a defective fan ... which would really blow!). #;-)



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10.5: More control of fan speeds on iMacs and laptops
Authored by: ajmanik on Jul 31, '08 10:38:09AM
Have you considered integrating the small code fix at the URL below? Apprently it really helps reduce the CPU load of the application. http://www.lobotomo.com/cgi-bin/yabb/YaBB.pl?num=1195271718

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10.5: More control of fan speeds on iMacs and laptops
Authored by: BryanD on Aug 20, '08 04:07:20PM
No ... because that posting is bogus (or at least any time I've ever checked it, it's always been below 0.2%, normally 0.1%) and the change wouldn't be that simple in my enhanced versions.

If you want to verify this on your system, in the Terminal, run the command (on OS X 10.5.x):
/usr/bin/top -Swu -s 5
and see what you get under the %CPU column for FanControl.

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10.5: More control of fan speeds on iMacs and laptops
Authored by: troutski on Sep 17, '10 12:50:08PM

Hi, Downloaded and installed FC1.2 No temp readings for CPU, just default @ 32F work around?
Speed control works fine, just no temp reading...

thanks

late 06 imac 5.1 2.16g 20"



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