[MW Forums]

You don’t have to drive a Prius, have a worm bin out back, or keep a picture of Al Gore under your pillow to be concerned about saving energy and natural resources. It just so happens that reducing the amount of electricity your computer, monitor, printer, and other electronic devices use is both environmentally friendly and economical. It’s also easy. more

[cseeman]

I was under the impression that the Mac OSX does a lot of its Unix housekeeping at "odd" hours. How does going into sleep mode or turning it off affect that?
Does one have to resort to using things like Mac Janitor or . . .?

[daneb]

I don't think we need to be tree-huggers (no offense Oregon) to be environmentally conscious. Simply turning off lights when you leave a room will save more energy that unplugging your cell phone charger. I just think there are a lot of things we do in our normal routine that can save more energy than unplugging chargers and turning off monitors.

[freddiepingpong]

I just wanted to clarify that although the term "Watts per hour" was used throughout the article, it's essentially meaningless.
Watts are already 'Joules per second', so to say 'Joules per second-hour' doesn't communicate anything.
Watts tells you how much power is being consumed (in time), and kilowatt-hours tells you the total power consumed (without a time component).

[eromerSV]

Quote:

---

I don't think we need to be tree-huggers (no offense Oregon) to be environmentally conscious. Simply turning off lights when you leave a room will save more energy that unplugging your cell phone charger. I just think there are a lot of things we do in our normal routine that can save more energy than unplugging chargers and turning off monitors.

---

True that turning off lights (100+ watts) will save more than unplugging your monitor (4 watts). But those 4-watt "vampires" on all the "off" devices in your home or office really add up, because they're on 24 hours. 4 watts times 20 devices (monitor, cable modem, router, printer, stereo, toothbrush charger, ....) times 24 hours is 2 kwh per day, or 730 kwh per year. Times 300 million Americans is a lot of power -- dozens of extra power plants we would not have to build were it not for the vampires. Plug things into power strips, and turn the power strips off when you can. It saves you money, it's good for the country (less imported energy needs) and good for the planet.
And also turn out the lights when you leave the room.
-- Evan Romer
treehugger
Windsor, NY

[consumer_x]

The vampires also generate heat.
This means that you use more electricity to cool your house/office in order to offset the temperature increase... and those cooling appliances also generate heat which means use use even more energy to offset those ... etc, and etc.

[Netizen_Kane]

Turning off rather than sleep may save a few watts, but there's another disadvantage to shutting down. You lose everything you're working on. Applications and files get closed. Not good if you want to pick up where you left off.
Whatever happened to the deep sleep/hibernation mode Apple introduced a few years ago, which would save RAM contents to HD then shut down? That would preserve the working state of the computer and take only a few more seconds to wake up.

[moose_n_squirrel]

I use the "put it all on a power strip and switch it off" method, but you should read your device manuals before you plug them in. Epson printers, for instance, should be turned off with its own switch instead of a power strip because it screws up the internal timer chip that tracks when the last ink cleaning was. If you screw it up, you'll waste expensive ink.

Quote:

---

I was under the impression that the Mac OSX does a lot of its Unix housekeeping at "odd" hours.

---

As of Tiger, OS X is much smarter about when those scripts are run. You mostly don't need to use MacJanitor or let the Mac consume an entire overnight's worth of power just to run 5 minutes of scripts.

[derekm]

Quote:

---

I just wanted to clarify that although the term "Watts per hour" was used throughout the article, it's essentially meaningless.

---

No doubt, but it looks like some of it was already fixed.
Michael,
#2 really needs fixing and some explaining about the numbers of hours assumed to be off instead of sleeping, especially when assuming a yearly savings. Did you take into account all of Sat/Sun being off anyway instead of sleeping? What about Friday evenings?
Sue me for being a pedantic geek, but I have to worry about this stuff all day long and the attitude rubs off when I see sloppy tech analysis that is missing a lot of written assumptions that have major implications one way or the other on such an analysis.
Do computers really use 40 W when sleeping? If so, then I guess this calcualtion is right about the 4 cents/day if we assume that it is off instead of sleeping for about 10 hours per day. However, I personally like to be away from work more than 10 hours/day. What about desktops compared to laptops?

[michaelgowan]

You're right that number 2 should be fixed. First, it should be 40 watt-hours per day. And the missing details: I based that on an iMac that sleeps 14 hours per day and uses about 3 watts while in sleep mode. Laptops should use less power than desktops. You can go to energystar.gov to search for your computer to see how much energy it uses while active and while asleep.

[michaelgowan]

Thanks for correcting us -- we've updated the article to fix the mistake.

[cseeman]

Can you explain "smarter?"
Basically can I put my Macs (I have four networked) to sleep when they're not in use and expect the scripts to run anyway at some point?
When do they actually run?
During sleep? During the period they're on full power?
Do they run on boot or shortly thereafter if they've been sleeping during the period they'd run?

Quote:

---

Quote:

---

I was under the impression that the Mac OSX does a lot of its Unix housekeeping at "odd" hours.

---

As of Tiger, OS X is much smarter about when those scripts are run. You mostly don't need to use MacJanitor or let the Mac consume an entire overnight's worth of power just to run 5 minutes of scripts.

---

[moose_n_squirrel]

Quote:

---

Can you explain "smarter?"
Basically can I put my Macs (I have four networked) to sleep when they're not in use and expect the scripts to run anyway at some point?
When do they actually run?
During sleep? During the period they're on full power?
Do they run on boot or shortly thereafter if they've been sleeping during the period they'd run?

---

Two tech notes:
Maintenance Scripts
Running the Mac OS X maintenance scripts
In the second one, scroll down to Scheduling Under Tiger, where it explains a possible glitch that may still require occasional manual script runs.
However, the point is that even if manual intervention is still required, as of 10.4.2 that is much less frequent because the scripts are handled in a more Mac-like way now. If you read those notes you'll know as much as I do about it.
Does anyone know if the sleep timing glitch in the second tech note was fixed in any recent system updates?

[Dan Frakes]

Quote:

---

As of Tiger, OS X is much smarter about when those scripts are run. You mostly don't need to use MacJanitor or let the Mac consume an entire overnight's worth of power just to run 5 minutes of scripts.

---

Unfortunately, Tiger's "smarter" behavior has bugs that prevent it from working properly for many users.
That said, the benefit -- for most users -- of having these scripts run regularly is minimal.