F.A.Q for smcFanControl 2.4

How do install and uninstall smcFanControl?
smcFanControl is just an application. So after downloading, and unzipping it, drag it to wherever you want (e.g. the Application Folder). To uninstall it, just drag it into the trash. smcFanControl installs no permanent background processes or daemons. 
All changes smcFanControl does to the fan controlling get lost after you shutdown your computer (power off, not restart) or enter standby mode (as far as you don't have smcFanControl running) . Minimum fan speed then falls back to the system defaults values.

When I run smcFanControl and set a new minimum speed, will my fan speed still increase if the CPU load gets higher?
Yes, fan speed will increase as defined by Apple. smcFanControl lets the fans stay in automatic mode and just sets the minimum fan speed. However, the higher you set the minimum fan speed, the longer it will take for the fan speed to increase.

Why does smcFanControl asks for a login and password and which login/password do I have to enter?
smcFanControl needs the credentials of an admin-user to set the appropriate rights to be able to change fanspeed. You only have to enter it one time. The entered login and password are not saved by smcFanControl. They are just used for setting the appropriate rights.

I get a "smcFanControl has not been tested on this machine" warning. What does that mean?
Technically smcFanControl supports every intel mac, but it does not come with defaults for every machine. If you get the warning, smcFanControl tries to read out the fan-details directly from the System Management Controller. If you follow the instructions (no other fan control software is running etc.) you should have no problem running smcFanControl on a machine it has not been tested on.

How can I restore the Apple defaults for fanspeed?
Move the sliders to the left and hit apply. The lowest settings smcFanControl allows are the Apple defaults. The minimum default speed after Apple's latest SMC firmware update is 1000rpm for the MBP 15,4", 1500rpm for the MB 13,3". 2000rpm for the Core2Duo MBP and 1800rpm for the Core2Duo MB.

Why can't I set my minimum fan speed to 0 rpm?
smcFanControl only lets you set the fan speed in the range of Apple's min and max values. Setting it to zero is possible from the technical perspective but could probably damage your machine.

When will the new settings for minimum fan speed get lost?
The settings you chose for minimum fan speed will get lost in two cases and the machine will fall back to default values:
a) You enter standby mode and smcFanControl is not running (If its running it watches for standby and reapplies your settings when you wake up the machine).
b) You power off the machine.

Which sensor is read out for the temperature?
It's not the sensor on the CoreDuo CPU's. The advantage is, that there is no Kernel Extension loaded for temperature readout and temperature should always be reported (some CoreDuo's stop temperature reporting after some minutes unfortunately). The sensor readout is very close to what CoreDuoTemp reports, but its not exactly the same cause of different sensors.
 
What about fan-control when I am in Windows XP running Bootcamp?
At the moment you can not set minimum fan speed when you are in Windows XP (cause smcFanControl is a native OS X application). However if you set up a new minimum fan speed in OS X using smcFanControl and then restart into Windows XP, your settings don't get lost and that new minimum fan speed is used on Windows XP for that session. Some people have reported usage of this to make their MBP cooler and not crashing when running games under Windows XP.

Will there be a version of smcFanControl for Powerbooks or other PPC based Macs?
No, PPC based macs don't have an SMC controller. So the approach of smcFanControl does not work. It's possible that there are solutions to control fan speed on PPC based macs, but I am not aware of any.

Will there be a dashboard widget for smcFanControl?
Well, I think this is a nice idea. I am currently working on improving smcFanControl as an application. But maybe someone else is a good dashboard developer. The GPL sources of smcFanControl should be a good starting point.

Wouldn't it be even better to read out the temperature and set the fan speeds depending on the readout than just set the minimum fan speed and let automatic fan control as defined by apple do the rest?
Yes, that approach is even better and could make your machine running cooler, when you are at higher loads. BUT: I did not take this route for smcFanControl, cause it has some risks. Adjusting the fan speed to CPU temperature requires you have a program running in the background (e.g. a daemon) that adjust fan speed continuously . If that program ever crashes or becomes incompatible cause of a System Update (or the readouts of the temperature sensor get inappropriate) , the fans could get set to a wrong (too low) speed and this could probably damage the machine. In addition to that the fan-control-logic is quite complicate. An intel mac has about 10 temperature sensors, that are continuously read out and are used for monitoring and setting the right fan speeds. So it would be "not so great" to read out just the CPU temperature as a foundation for the fan-controlling.

I have got a MBP and smcFanControl is reporting 0rpm for one of my fans?
In that case the fan did not report any data to smcFanControl. It is possible that one of your fan's is dead. Please check your computer with the Apple Hardware Test (it's on the DVD that comes with your computer) and see if it reports a failure with one of your fans. 

What are the main-differences between Version 1.2x and Version 2.x of smcFanControl?
	•	Version 2.x is a completely rewritten application.
	•	Version 1.x was a "regular" application located in the dock. Version 2.x sits in the menubar for quicker access to the fan settings, easier monitoring and a better overall user-experience
	•	Version 2.x supports every intel mac
	•	In Version 2.x you can save different fan-settings as favorites and active them with just one mouse-click
	•	On portables you can autoapply different fan-settings, when the powersource changes. So you can cool down your macbook automatically when its loading the battery (and is typically running hotter).
	•	Version 2.x has got an "add to login-items option" now
	•	Version 2.x uses standard OS X authentication now
	•	Version 2.x uses the Sparkle-Framework to automatically check for updates

Sourcecode: https://github.com/hholtmann/smcFanControl