Energy Efficiency (Can you help to settle a family Mac debate?)

[turtlehills]

I come from a Mac family (yay!) but my mother recommends that I sleep my computer if I leave for a few hours or even overnight and I am inclined to turn it off every time I leave for more than 20 minutes to save electricity.

I recently edited a new environmental book at work, in which we recommend that people consider using Macs because they use less energy than virtually all PC's.  And the book also talks about the tremendous amount of energy that could be saved if everyone would turn out their computers at night.

However I haven't been able to find this information for Macs - whether it's better in terms of energy efficiency and wear and tear on the computer to sleep it or turn it off and on again, even 3 or 4 times a day?  I'm sure I could ask at my local two-story Mac Store (in LA at The Grove, check it out sometime!) but I thought someone at TS might know?

Thanks!
Turtle Hills

[Xairbusdriver]

If it's not doing anything productive there's no point in having it on whether it's 'sleeping' or not. Since the CRT is no longer used by most Macs and even PCs there's little reason to even let them sleep or have the monitor go black. Even when  CRT/TV is switched OFF, it is probably still using 10 - 20 watts of electricity just so it can come back to life almost instantly. I don't think LCDs need/use that much energy even when they are ON. But even when the machines are 'sleeping' some energy is being used. So, if it's not doing anything, turn it off, IF energy saving/cost is the major concern.

If longevity is more important, it has been argued that the cold/heat/cold/heat/... cycle is what damages silicon more than anything else. In that caes, an argument can be made to leave things ON but asleep.

If you do decide to let 'sleeping' computers lay about, you might think about putting those cpu cycles to some good use. There are dozens of 'shared computing' applications available, even for a Mac. I just got my version of Stanford University's Protein Folding app working on my new iMac. It now runs 24/7. I let the screen 'sleep' but not the cpu, so I'm using more energy than a completely sleeping computer. But I feel I'm contributing to the search for a breakthrough for a better medical understanding of the causes of many brain related diseases; something that seems to be affecting me as I age!

In other words, the answer to the question depends on your definition of what is more important; energy saving, mechanical problems with silicon ( most 'sleep' modes put the drive in 'park' ), or useful production from a device that is great at repeated, tedious, boring operations that can provide help to civilization.

But, I would never suggest arguing against ones parents/spouse in any 'discussion!'

BTW, <Team Mac OS X> is now ranked number 7 in the Folding@Home stats! Obviously irritating news to many of the super-high-speed-PCs-are-not-toy-computers crowd!

[turtlehills]

Wow, thanks!  I didn't realize I could use my Mac as a living donor!  Very cool.  
So now I get to decide if I want to:

- Save money
- Save energy and the planet (per Al Gore)
- Save my beloved Mac
- Save people with brain-related diseases

Oh my!  At least now whatever I do, I am helping to save something.

I forgot to mention that I have an iMac which changes things a little.
I think you're right about the arguing - at least now I can say, "We were BOTH right!"  

Thanks, as always,
The Tortoise

[Mayo]

I recall reading that an iMac uses 35 watts/hour when sleeping. Don't Quote Me On That...

It makes no sense to me to leave anything on when it isn't in use, and all the appliances that now sport so-called "standby modes" consume a LOT of energy when it is all added together. It is always an eye-opener for me when I travel to Europe and experience first-hand industrialized societies that have integrated energy-savings habits in many aspects of daily life. We in the U.S. could learn something from their example...

Power-saving aside, there is another practical reason for shutting-down a Mac on a regular basis.  The longer a Mac runs without shutting-down the more RAM is tied-up, to the point where much of the RAM is "spoken-for" in some manner... And the Mac can noticeably slow down. This can happen over 1-3 days, more or less, depending on a number of variables.  I use iStat Menus to monitor my memory usage and it is enlightening to watch the RAM usage increase over a 1-2 day period of time. Merely restarting a Mac will free-up significant amounts of RAM.

It amazes me that a lot of people see themselves as being sooo busy that they cannot be bothered to wait a minute or two while their Mac boots-up.

[Highmac]

I'm a switcher-off.... If we know we're going to be using the Mac on and off during the day, we let just the screen sleep. The computer's always turned off at night, as is the Netgear.
Sometimes, however, I want to record a radio or TV show late at night; EyeTV will start the iMac up (remember to hit the mute key before you shut it down - don't want that Mac chord waking the whole house in the middle of the night!), then I generally set the shutdown schedule to switch it off about 30 mins after the show is due to end.

[Paddy]

Mayo, according to this Apple document, iMacs consume about 5W of power when asleep:

http://docs.info.apple.com/article.html?artnum=34571

Comparison of iMac's energy usage with a desktop PC and a fascinating site about cutting energy expenditures:

http://michaelbluejay.com/electricity/computers.html

More comparisons here:

http://tingilinde.typepad.com/starstuff/20...energy_use.html

General info about Macs and energy use:

http://www.apple.com/environment/energyefficiency/

Bottom line, you will save energy by turning off the iMac - and it won't hurt it either. So you can eliminate one of those options ("save my Mac") and you're down to three.

I let my G5 sleep after 15 minutes, and no...I don't turn it off at night. I do automatic backups at 1:30 and 2:30 a.m. I am on it off and on all day long - turning it off during the day really isn't an option. The G5 uses about 11 W when asleep - 250 to 300 when awake and busy.

[FLASH1296]

Firstly, turning (any) computer On and Off frequently STRESSES the Hard Drive in the same way that "Stop and Go" traffic far more rapidly depreciates your car than cruising along a highway under cruise-control.

Secondly, wattage on a sleeping Mac is truly negligible -- but for those who are hyper "green" there is a better alternative - "hibernation"  The only drawback is that you can expect your Mac to take 5 or 10 or 15 seconds or more to awaken.

I have several Macs, including a dedicated file-server on a G-5 iMac  that has not been turned off in 2 years. (It is rebooted twice a month)
My laptops are only turned OFF if they will be unused for more than 48 hrs.   YMMV

[Gregg]

QUOTE(Mayo @ Dec 4 2007, 03:24 PM) <{POST_SNAPBACK}>

It amazes me that a lot of people see themselves as being sooo busy that they cannot be bothered to wait a minute or two while their Mac boots-up.

Well, I guess I can't make that "arguement"...  

[Mayo]

Like I said, DON'T quote me...! I didn't want to take the time to verify my memory...

[Gregg]

QUOTE(Mayo @ Dec 4 2007, 03:24 PM) <{POST_SNAPBACK}>

I recall reading that an iMac uses _______. Don't Quote Me On That...

What you actually said is not That which I quoted.

[Xairbusdriver]

Many of us use utilities like SuperDuper, Cocktail, Onyx, etc. during the wee hours of the morning and most of them can also be set to Restart your Mac, thus negating the need to do so manually and waiting for the machine to be ready when you sit down in front of it (not sure if it would also be ready if you sat down behind it...that may require further study...).

And I also agree that it should be shut down, if it isn't doing anything useful while you're not using it (mainly sleeping). The question is, what do you consider "useful?"

[chriskleeman]

Look at this:

[hingyfan]

I read somewhere, maybe here, that shutting off a computer when not in use will save $200 a year. That seems like a lot but that's the way i remember it. Of course I still leave ours on.

[Gregg]

QUOTE(hingyfan @ Dec 6 2007, 12:16 PM) <{POST_SNAPBACK}>

I read somewhere, maybe here, that shutting off a computer when not in use will save $200 a year. That seems like a lot but that's the way i remember it.

At the rates we pay, seems a pittance!

[Mayo]

QUOTE

Many of us use utilities like SuperDuper, Cocktail, Onyx, etc. during the wee hours of the morning...

Of course, said utilities could be scheduled to run during the time when the computer is being used by someone (or at the end of the day when using SuperDuper!), or even done manually, negating the need to leave the computer running 24/7.