smcFanControl - Manually set some Macs' fan speeds

Oct 18, '06 09:39:00AM

Contributed by: robg

The macosxhints Rating:

[Score: 10 out of 10]

[This is the Pick of the Week for the week of October 16th]

When the MacBooks were announced, I made my purchase decision relatively quickly -- I wanted something faster than my PowerBook G4, but didn't want to spend $2K+ for a MacBook Pro. The price and performance of the MacBook struck a sweet spot with me, and I purchased one of the first black units to show up in the Portland area (I waited to see them in person so I could judge the reflective screen's performance for myself). Generally, I've been thrilled with the MacBook's performance, despite having to send it back to repair a way-too-warm power adapter (the repairs were successful).

The only two things I'm disappointed in are the size (I love the 12" form factor) and the high case temperature (especially in the bottom left corner). While I can't do anything about the first problem, thanks to smcFanControl, the second issue is now completely within my control. As seen in the picture at left, this simple app gives you a slider to set the minimum speed for your laptop's fan(s). It works with the MacBook, MacBook Pro, and Intel-powered minis, and it works well.

Apple sets the fan's speed at 1,500rpm, and this works well when I have the machine on the desk. But on my lap, it gets just a bit too warm. Using smcFanControl, I upped the speed to 3,000rpm, and saw a notable (two to four degrees Celsius) temperature drop. The case was cooler to the touch, too. Later today, I hope to get some more empirical data through a USB temperature probe. When I set the fan to max speed, I saw an even nicer temperature drop ... but I was having trouble enjoying it, thanks to the 747 that seemed to be landing nearby. Perhaps if you're wearing noise a cancelling headset it would be bearable...

The downsides? More fan noise, obviously -- although 3,000rpm was fine for my ears (though I probably wouldn't use that setting in a library). Perhaps slightly reduced battery life, and a bit more wear and tear on the fan components. But in exchange for a cooler lap, I think it's worth it. It's important to note that smcFanControl is just an app -- it doesn't install any components (unless you want it to run at startup). I've been using it to increase the fan speed when I have the machine on my lap, and reduce it again when it returns to the desk.

smcFanControl won't allow you to set the fan speed lower than Apple's default, so there shouldn't be any risk from using this app. Still, when mucking with hardware, you never know what might go wrong, so no warranty is expressed or implied with this hint!

Comments (8)


Mac OS X Hints
http://hints.macworld.com/article.php?story=20061018093936249