If you are one of the few people who have ever been in my office, you probably remember one thing in particular: it is unbearably HOT. Computers kick out a lot of waste heat, my PowerMac is especially hot. This particular model is known by the nickname "wind tunnel," it is notorious for the noise of the high powered fans it uses to vent all the heat. And all the heat goes out into my tiny office.
I recently moved into a new apartment, and relocated all my computer equipment into my new office in the second bedroom. When I put the utilities account in my name, the company said the August bill for last year was only $50, but when I got my first bill, it was $150! Either the previous tenant was exceptionally frugal and never ran the air conditioning, or else my computers were using a lot more power than I ever suspected.
I did a bit of research, discussed the problem with a few people, and the general opinion was that the computers didn't really consume that much electricity, the big energy cost was the extra air conditioning to cool the excess heat the computers generate.
In the course of this discussion, someone suggested I look at an old software hack for my machine, called CHUD. It is an old Apple developer utility that adds "processor nap mode," it sleeps the processor between cycles during times of low CPU demand, reducing power consumption and waste heat output. I installed it and miraculously the chip temperature dropped by nearly 30 degrees Centigrade, and the exhaust heat dropped to tolerable levels. I just poked the button and suddenly my office was cool again! The air conditioning stopped running all the time, I haven't received my latest utility bill yet but I expect it to be considerably lower.
I rarely reboot my computer, so about a week later when I installed some new software and restarted, I didn't think anything about it. But about an hour later, I felt like I had a fever, I was burning up. At first I thought I caught a cold or flu, but then I checked the computer's temperature sensors and discovered it was running hot again. Nap Mode isn't persistent across reboots, you have to poke the button after every reboot. That's not such a big deal since I usually run for weeks and even months without rebooting.
But alas, this story has a sudden surprise ending, unexpected even by me. As I was writing this story, in the background I was installing the latest update to MacOS X, version 1.4.3. Unfortunately, Nap Mode is now disabled, and my office is getting hot again. I am trying to get CHUD to work again, but it appears to be impossible. Oh well, it was nice while it lasted.
Update Nov 1, 2005: I got it working, and my office is cool again. A few years ago, I wrote a new variant of Murphy's Law I call "The Idiot's Law," and this is a perfect example. I asked for help with CHUD from the Accelerate Your Mac website. They published my plea for help, and then suddenly Nap Mode spontaneously started working again. The Idiot's Law: Whenever you ask for tech help in a public forum, your problem suddenly resolves itself in a way that makes you look like an idiot.