In System Preferences go to Security and Privacy and you can set it to require a password; Immediately, 5 seconds, 1 minute, 5 minutes, 15 minutes, 1 hour, 4 hours after going to sleep.
Mine goes to sleep after about 17 minutes of inactivity but I have it so I only have to re-enter my password if it's been in sleep for an hour or more.
I leave it on 24/7. No sleep. I do put the display to sleep when I walk away though. I set up the top left corner as a hot corner that sleeps the display. So I just swipe the mouse pointer to that corner as I get up and it goes off
isn't that when leaving the mac on all the time, it supposed to reduce the life of the hard drive. when the last HDD failed on my imac, I was told by someone. Now I turn off my iMac most of the days before bed. my was a late 2006 imac
Thanks for taking the trouble to respond. However it seems the problem is a
bug in late 2012 iMacs. 21" have a fix, 27" don't yet, see:
https://forums.macrumors.com/threads/1509682/
Mine did that when I had Wake on LAN enabled. Turned that off and it never did it again. But it wasn't often like you're saying, happened once an hour or two.
Why would you have to keep it on all the time is it just because you can't be bothered to turn it on each morning?
It wastes electricity and might prematurely age the computer so yeah I'll turn it off while I'm sleeping and out of the house.
As a simplistic analogy: the simple act of turning on a light bulb uses more power than leaving that bulb on for two hours. Considering how often conscientious (and ignorant) "keep it off when not in use" types turn lights off & on, that's wasting a whole lot more power - and burning bulbs out a lot sooner - than "wasteful" people who leave lights on most of the time.
Ditto computers, just on a different & more complicated scale.
Actually, you are both somewhat right and somewhat misinformed.
The discussion seems to be focused on power, which is where incorrect conclusions are reached. Power is an instantaneous parameter that, in the case of an incandescent light bulb, is indeed higher when it it first turned on due to the time it takes for the filament to come up to operating temperature. But this time is only a fraction of a second. You are not billed for instantaneous power, but rather for energy used. Energy is power times the amount of time it exists. That is why your electric bill is for the number of KW-Hrs (an energy unit) rather than for KW (a power unit).
Using the 60 W lightbulb as an example, the power when first turned on might be say 200 W but only for perhaps 0.3 seconds and then the steady state 60 W lasts for the duration of the time it is operating. If you pay 10 cents per KW-Hr for electricity, the cost for the turn-on high power operation would be 0.002 cents, and the cost for operating the bulb for each hour thereafter would be 0.6 cents. Thus, the actual utility cost of the turn-on transient is indeed inconsequential. (This is a simplified example for ease of illustration. In actuality the turn-on transient will have an exponential waveform which must be integrated to calculate the energy. But the result will be similar.)
So, from a purely utility billing point-of-view, the cost is minimized by turning off the bulb when not in use.
However, this cost is not the only criterion in the case of light bulbs. You may have noticed that lots of times an incandescent bulb will fail immediately when it is turned on rather than later. This is because the turn-on condition with the high instantaneous power is indeed a very high stress condition for the filament of the bulb, and is perhaps the primary failure mode for incandescent bulbs. So, from a reliability viewpoint, failures can indeed be reduced by minimizing the number of times the light is turned on and off.
Now, lets turn our attention to computers rather than lightbulbs. The failure mode discussed above does not exist with a well designed computer power supply - and the power supply in your Mac is indeed a very good one. There are no filaments to burn out! The Mac power supply should handle tens of thousands of turn-on cycles without any appreciable reliability reduction. So, in my opinion, how you decide to operate your Mac in terms of keeping it on or turning it on and off should be decided by your own assessment of operating cost vs. convenience and not by any concern about reliability.
For my own iMac, I have it set to turn off the display after 1 hour (reduces power consumption by about half) and to go to sleep after 3 hours (very substantial power reduction).
Me too. I shut my iMac down more often with the Fusion drive. No point in it being a power vampire when not being used.I just activated sleep mode on my old one, but on the new one with the Fusion Drive i see no need to because it boots in under 15 seconds and loads everything extremely fast.
Not to derail the thread, but I call your bluff. Prove it.
There is no way a 60W light bulb uses 120W when you first turn it on for it to start producing light. What you are saying is full of $!@# and I ask that you enlighten us with a credible source proving your point.
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You don't know how an incandescent bulb turns on and subsequently functions, do you?
When it's off, it's cold. The filament is just a wire shorting + to -.
When you turn the switch on, there is no electrical resistance. You've just shorted 110V of darned near infinite current source to ground. That's a LOT of power running thru the bulb. That initial power surge is huge.
With all that power running thru it, it heats up. As it heats, resistance increases - the filament gets hot, and starts glowing, which is how the the device makes light. After a few milliseconds the current flow and resistance balance out and your light is on.
So...when you turn the light on, the process of heating the filament up enough to glow uses a lot of power. Not for long, but a lot.
A simple experiment evaluating this is here: http://physicsed.buffalostate.edu/pubs/TPT/TPTDec99Filament.pdf
Conclusion/measurement is that at turn-on a 60W bulb draws about 7A. Given power equation P=IV, that means the light uses 840W turning on.
How long this takes, of course, is the real question. colodane takes a good stab at this. Factor in wear of repeated cycling, bulb cost, burnout frequency, AC power complications, etc. and you'll work out what it costs.
I suggest you not insist someone "is full of $!@#" when you don't know how something as simple as a light bulb works.
Meh.southerndoc said:There is no way a 60W light bulb uses 120W when you first turn it on for it to start producing light.
it actually says in the manual that comes with your iMac that you should really only shut it down if you are going to be away from it for more than a couple of days.
If youll be away from your iMac for less than a few days, put it to sleep. ... If you wont be using your iMac for more than a few days, shut it down. ... The only way to turn off power completely is to unplug the power cord.