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. With these settings, the HD in our iMac stays below 110F/43.3C (other temps were not an issue and stay similarly low). The current settings on my MacBook Pro 2.33 Core 2 Duo are:

Settings will vary depending upon your environment and system usage patterns. e.g., to generate a version for the Mac Pro that uses different sensors to control different fans (or groups of fans). I've also tried to make it easy for anyone who might want to modify the source code and adapt it to other systems. (The GPU-based operation can be useful if you play games.) There are some other minor enhancements, noted in the Read Me file.

The MacBook/MacBook Pro version allows use of the CPU and/or GPU temperatures to drive the fans. The iMac version uses separate sensors to drive the control of each of its three fans. These versions also have some extended control capabilities over the original FanControl.

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. To that end, I decided to modify the open source (GPL) FanControl to work with our iMac. 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. This most recent version adds support for every current MacBook, MacBook Pro, MacBook Air, and Mini.We take great care to ensure that our systems run with reasonable temperatures as that helps extend their lifetimes. As with any settings-tinkering software, you'll want to use smcFanControl judiciously-but fortunately this application always keeps fans in automatic mode (so speed will increase along with CPU load) and never lets you set the fan speed below the Apple-recommended minimum. SmcFanControl lets you monitor the current temperature (in Celsius or Fahrenheit), assign different minimum speeds for each fan using sliders, and even apply different settings when your power source changes (for example, going back to default fan speed when using battery power). This free, GPL-licensed utility has a single purpose: letting you increase the minimum speed of built-in fans, so your Intel computer will run cooler. If you've got burnt thighs from an old MacBook Pro or you notice that your computer is always overheating and crashing from using CPU-intensive apps (like playing PC games in a virtual Windows environment), you might want to check out smcFanControl. SmcFanControl lets the user set the minimum speed of the build-in fans.

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