Catnap Fever


Q: Care to settle a bet? My roommate insists it’s always best to shut down your computer whenever you’re going to skip out for more than three hours, to save on electricity costs. But I’ve heard that shutdowns can damage a CPU, so the smart move is to leave your machine in “standby” mode and never switch it off. Who’s right?

You two are haggling over geekdom’s version of the intractable “Tastes Great/Less Filling” debate. Mr. Roboto so wishes he could declare an obvious victor, but the answer’s a bit too muddled for that. Both sides have been distorted by urban legend, yet both have their merits, too.

Let’s start with your contention that too many shutdowns can put undue strain on a computer. Mr. Roboto’s heard a couple of theories as to why this might be, the most popular being the notion that CPU-melting heat doesn’t dissipate after shutdown, since the cooling fans cease to whir. Products like PC Mods’ Power Down Protector ($10 from promise to “extend the life of your chip significantly” by keeping your fan running for a few minutes. Another school of thought holds that powering on and off sends a nasty jolt of electricity coursing through the system, one that slowly erodes your machine’s innards.

There may be something to the heat theory, but if so, it’s only for a tiny subset of heavy users—like, those who play Unreal Tournament on a 3 GHz PC for 10 hours straight. And the electricity paranoia might have been well-placed back in the era of Kaypros, but even the crappiest contemporary Gateway is hearty enough to withstand numerous shutdowns. So there goes the crux of your argument, Mr. Roboto reckons.

But your roommate isn’t exactly ready for Mensa (, either. For all their myriad circuits, computers aren’t energy hogs—especially newer models, which usually have Energy Star or equivalent conservation technology built in. Let’s do a back of the envelope calculation, shall we? Mr. Roboto guesstimates (liberally) that the machine he’s writing this column on consumes between 80 and 100 watts while being used moderately. Based on Con Edison’s current rates, then, to keep this puppy on all year would cost about $140. Shutting it down for 12 hours a day would swell the coffers by $70.

That little slab of math, however, doesn’t take into account the fact that today’s computers are trained to go into standby mode when left idle for too long. That allows you to quickly relaunch the machine by pressing any key, thus saving you the pain of having to reboot entirely. Energy consumption drops by 70 to 90 percent in standby, so Mr. Roboto’s betting the true savings from shutting down would be somewhere in the neighborhood of $15 to $20 per year. (If your machine doesn’t automatically stand by after a set period of idleness, check Power Options in the Control Panel.)

You make no mention of your roommate’s environmental consciousness, but keep in mind that it’s not all about the cake; conserving energy’s always a good thing for the planet. (Contrary to what you might think, Mr. Roboto and his cyborgian brethren do not look forward to the day the earth becomes a post-apocalyptic wasteland à la Hell Comes to Frogtown.) And older versions of Windows, like 95 and 98, tend to crash after spending too much time standing by.

If you’re a PC user, the advice here is to opt for hibernation, which saves your work to the hard disk before winking out. On XP, you can hibernate by selecting “Turn Off Computer” from the Start menu; hold the shift key, and the standby icon morphs into “Hibernate.” As for Mac devotees, the sleep function works just as well. Shut down entirely every once in a while, to flush the pipes, so to speak—rebooting has a way of getting rid of junky temp files and other performance-slowing nuisances.

This being the season for sudden thunderstorms, it’s also worth noting that lightning can fry your box if it’s in standby mode. Not bloody likely, for sure, but a surge protector isn’t exactly a mammoth investment. And while you’re at it, do Mr. Roboto a favor and call a truce with your roomie. You were both a little wrong and a little right. A big hug will work wonders.

Input questions at