Did I read correctly? My new iMac 21.5" uses 240 W. an hour?

Joined
Mar 9, 2010
Messages
30
Reaction score
0
Points
6
Location
San Diego, Ca.
Your Mac's Specs
3/10: Purchased an iMac 21.5" 3.06 GZ, 500 MB, 4 GB
Is that true? That seems like a lot, but never bothered to compare it to my 4.5 yr. old PC.
 
Joined
Sep 13, 2009
Messages
212
Reaction score
1
Points
18
Location
Pittsburgh, PA
Your Mac's Specs
27" iMac Core 2 Duo, 4GB 1067 MHz RAM, iPhone 4S
Where did you read this?
 
C

chas_m

Guest
No, you did not read correctly.

The iMac tech specs page clearly says that that **MAXIMUM** continuous power is 241W for the 21.5 version.

Nearly all of this is of course due to the screen. The 24" Cinema Display, for example, uses 212W as max. continuous power.

So, if we were to imagine the iMac as two separate components and assume the 21.5" screen used 200W max continuous, that would mean the COMPUTER part would use a maximum of 41W. And again, *maximum* means exactly that -- in routine use it would use less power than that.

This is probably why the iMac -- alone among all-in-one computers of this size, as far as I can tell -- is EnergyStar rated.

If your 4.5-year-old PC is hooked up to a CRT monitor (as would be appropriate for its age), then you can rest assured you are using WAY WAY more power to run the monitor there than any LCD monitor made by anyone. If you have an LCD monitor on it, you're still using more power than the iMac's LED-backlit screen at the same size and resolution.

Here's more information on this if you're interested.

Greenpeace themselves acknowledge that Apple has taken the lead on making their product line as energy-efficient as it can be.
 
Joined
Apr 9, 2009
Messages
2,073
Reaction score
68
Points
48
Location
Ithaca NY
Your Mac's Specs
13 inch alMacBook 2GHz C2D 4G DDR3, 1.25GHz G4 eMac
Good stuff, Chas.
 
OP
N
Joined
Mar 9, 2010
Messages
30
Reaction score
0
Points
6
Location
San Diego, Ca.
Your Mac's Specs
3/10: Purchased an iMac 21.5" 3.06 GZ, 500 MB, 4 GB
Well, maybe we're "splitting hairs" here? When I said my iMac will use 240 watts per hour, I was, of course, including the use of the monitor since I would seldom use the "computer" part without the screen being on. Isn't that true or am I missing something (which isn't hard to do). So, wasn't I "right" (you said I didn't read correctly - :[ ) when I said I read the amt. of wattage is 240 Watts? Or are you saying that it's rare to use it at its maximum. If that's the case, wonder what would the "average" usage amount to in wattage per hour? (230 watts? lol) Especially, since the iMac is an all-in-one and not with a separate tower, how often does one turn off the monitor but keep the computer on anyway? Just asking ...
 

pigoo3

Well-known member
Staff member
Admin
Joined
May 20, 2008
Messages
44,210
Reaction score
1,418
Points
113
Location
U.S.
Your Mac's Specs
2017 15" MBP, 16gig ram, 1TB SSD, OS 10.15
Is that true? That seems like a lot, but never bothered to compare it to my 4.5 yr. old PC.

Well if it makes you feel any better...if your iMac had a CRT display instead of an LCD...it would use a good bit more wattage.

If you want to do your part to "be green"...you could either turn the brightness down as low as it will go (but still viewable)...or turn your computer off!;)

Another option could be to sell your iMac & buy a laptop!:) I think that the low-end MacBook uses a 65 watt power adapter.

- Nick
 
Joined
Jan 27, 2007
Messages
5,658
Reaction score
159
Points
63
Location
*Brisvegas*
Your Mac's Specs
17 inch 2 GHz C2D imac (5,1) with 3GB DDR2 RAM, X1600 (128MB memory) GPU - OSX 10.6.3
to chas_m:

Your post is not entirely correct. In a Apple display it has to have it's own power source to power up and use the display. So that's the 212W you talk about. But the imac does not need 2 power sources (screen and computer). It only needs the one to to power the screen and the computer workings behind the screen. So I'm sure the power usage of the screena nd the computer in the imac would fluxuate over time.

So my point here is a computer and seperate screen or the same computer and screen as an all in one have slightly sifferent power usages due to the fact the seperate ones need 2 power sources and extra parts for that where as the all in one needs only one power source for everything.

Just a really minor point. But otherwise what you says makes basic sense.
 
C

chas_m

Guest
Well, maybe we're "splitting hairs" here?

No, we're not "splitting hairs." You misread.

"Maximum" is a word that actually has a meaning.

Isn't that true or am I missing something (which isn't hard to do).

Again, you're missing something. That something is "maximum."

To achieve a use of 241W/hour, you would have to have the monitor on at full brightness, doing something like playing a complex 3D game, running the GPU and CPU at 100% all cores, plus spinning the optical drive, plus typing and mousing continuously, plus having bluetooth and internet active and functioning. For an hour. IOW, you would have to be maxing out every part of the Mac's functionality continuously.

Do you find yourself doing that on a routine basis? No? Then the 241W/hour idea isn't accurate and doesn't apply.

If that's the case, wonder what would the "average" usage amount to in wattage per hour?

Apple doesn't supply that information and I wouldn't like to speculate (because it depends on a LOT of factors, starting with screen brightness), but there's a device called a Kill-A-Watt that you can buy and use to measure this.

You still haven't explained a) why this is important and b) why you feel it is high in comparison to any equivalent machine. As previously explained, LED-backlit screens use less power than flourescent-backlit LCDs, which it turn use a lot less power than CRTs. Likewise, chip manufacturers (particularly Intel) have been continuously working on reducing the power draw of their processors even while making them more powerful, meaning a computer from just a few years ago that was less powerful, didn't have all the additional features today's computers have (such as powered ports, Bluetooth and wireless cards by default, fast hard drives, faster optical drives, etc etc) drew a max combined of anywhere from 250-400W/hour.

But the key thing to understand is that when one says "max" that's exactly what one means -- a rarely-achieved state of full exploitation of all power-drawing resources. Even older computers typically draw much less than their max power consumption -- anywhere from around 60W to their upper "max" limitations. If you're word processing on a dim screen, you're using a HECK of a lot less power than if you're playing CRYSIS on a max-brightness screen.

So, in short, the iMac does *not* draw 240W/hour, which is what you claimed, in typical use.

Had you actually read the link I provided, you would have learned that Apple takes LOTS of steps to minimize electrical use when the computer is "idling," which is what it is actually doing most of the time one uses it. This is why Greenpeace and the government have both given the machine high marks.

Especially, since the iMac is an all-in-one and not with a separate tower, how often does one turn off the monitor but keep the computer on anyway? Just asking ...

It's called "display sleep" and most of us have it available all the time. Since the bulk of what a computer does is wait for input from the user, one can set the screen to go blank after a certain number of minutes of inactivity. The exact amount can be adjusted (if one is a slow reader for example, one might set it to a longer time). Adjusting the brightness also has a dramatic effect on how much power the screen uses (and again, the screen is the major culprit of energy use). This is precisely why devices that are dependent on battery, such as notebooks and the iPhone (et al) have such quick "dim the screen" and "go to black" timings.
 
Joined
Jan 19, 2008
Messages
4,695
Reaction score
73
Points
48
Location
houston texas
Your Mac's Specs
09 MBP 8GB ram 500GB HD OS 10.9 32B iPad 4 32GB iPhone 5 iOs7 2TB TC Apple TV3
I am surprised Greenpeace is not up in arms over gaming computers with 1000 watt power supplies.
 

pigoo3

Well-known member
Staff member
Admin
Joined
May 20, 2008
Messages
44,210
Reaction score
1,418
Points
113
Location
U.S.
Your Mac's Specs
2017 15" MBP, 16gig ram, 1TB SSD, OS 10.15
there's a device called a Kill-A-Watt that you can buy and use to measure this.

Yeah...I always wanted to get one of these (or a similar device)...for the very reasons mentioned. And not just for measuring a computers watts used...but other devices as well.

And as mentioned...a variety of factors go into the exact watts used for a device...making exact estimates difficult without a meter.

- Nick
 

Shop Amazon


Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
Top