Saturday, 2 December 2006

Undervolting My MacBook

My dear friend Paul commented in a recent e-mail that I hadn't posted anything Mac related recently (apart from the new ads).

He also passed on a link to an article on "undervolting". This is sort of the opposite of what the speed-loving overclockers do. My current motherboard, the Asus P5B, comes with software that allows this.

That got me wondering whether there was any undervolting software available for my MacBook. After all, lowering the CPU speed should both decrease the heat the laptop outputs and surely must increase its battery life.

So, I had a quick google and discovered CoolBook. I've just downloaded a copy and will put it through its paces tomorrow. Here's an article someone else wrote about it.


So, I tried it out today. With the clock speed and voltage at their lowest settings, it seems to have increased battery life by around 45 minutes, with no discernible drop in performance for my normal use.

I haven't tried doing anything seriously heavy with it turned on, so I can't say whether there may be a performance hit for CPU intensive tasks, like transcoding video, or compiling a Java project, but even if that turns out to be the case, I can always turn it off when I have such work to do.

My MacBook also seems a fair bit cooler now, too. According to the temperature gauge in CoolBook, about 10°C cooler.

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