# Leaving a computer on 24/7



## Gayble.com

Alot of people have told me that if you leave your computer on 24/7 it saves more electricity than turning it off and on each day, and then some of my other friends say the opposite, they say that leaving your computer on 24/7 uses *more* electricity.

So, which is true? and how?

They say that when you turn a computer on/off usually (3 times a day or so) it uses more electricity than leaving it off.. well, what I want to do is leave my computer on 24/7 but I'm just worried that my mum will have a heart attack from electricity bills so I need to make sure.. can anyone bring some light on this issue? 

Here are my computer specs:

AMD Sempron 2600+ Skt 754
512MB DDR400 RAM
80GB 7200RPM Hard Drive
Geforce FX5200 128MB AGP
Pioneer 16x (DL) DVD Writer
400W Deluxe ATX Case
ViewSonic 17" Flat LCD Monitor


I've heard that the cooling system you use (fan, etc.) can also help with decreasing the electricity the computer uses..

any computer pro's, experts and the like, please help!


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## lowcar100

The more fans you use the more electricity you will use, the less heat you will have though.

I dont think it would matter if you left your pc on all the time if you had it in "sleep mode" when you werent using it. but as far as electricity goes i believe that it is determined by what you are doing, if you are playing a demanding game then it will probably take more electricity sitting idle or in sleep mode should take minimal but im not sure, about 90%

These people that are telling you it takes more electricity to start it up and shut it down must be relating it to a car's engine, much more wear and gas used on start up, otherwise people would probably shut the cars off at red lights eh?


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## Gayble.com

No, I don't play games, I only have Mozilla FireFox, Outlook Express and MSN Messenger open most of the time. I'll take your advice and try going into stand by when I'm not using it.


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## SFR

Well, your monitor and hard drive(s) typically use the most electricity... that is why Windows offers energy saving options... you can set a time for monitor to automatically turn off and your hard disks to stop spinning.... also there is standby mode and hibernation (mostly for laptops) mode...


I read (might not currently be true, but in the past) the most "wear and tear" on machines occur during the boot and shutdown of the computer. That is why I leave my machines on 24/7.


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## vortmax

yea, for solid state devices, all wear is due to thermal stress.  Shutting it down lets the parts cool and contract.  Turning it on makes them heat up and expand.  The more cycles you do, the more wear.  It's better to keep the components at a constant temp by keeping the computer on.

For hard drives, it's best to let the OS turn them off since keeping them spinning will wear out the platter motors eventually.

Computers really don't use more energy during startup and shutdown then while running unless you're using speedstep and/or hardware controlled fan speed.


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## Gayble.com

Ok, I've set my computer to turn the monitor off after 2 minutes, hard disks off after 10 mins and go into stand by after 30 mins. I'll try leaving the computer on 24/7 for one month as you guys have advised 

Well, I'll post this on as much forums as I can (tech, computer related, etc.) I have to make sure that what I do will not cause a big effect on the electricity bill, my mums life is on the line  and I don't want her to faint or have a heart attack next to the mail box


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## kof2000

is all good until it catches on fire and burn the house down.


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## Geoff

The only harm in keeping your computer on all the time is using alot of electricity, and wearing out the components.  For example, a power supply may only be good for 100,000 hours, but of course you will probably get a new one within 11 years, lol.

So its pretty much just the electricty aspect.


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## vortmax

my computer has been on since August 1st when I moved here.  Before that it had been running for about 3 years straight, except for periodic power failures and shutting it down to move it or change hardware.  It's running like a champ.


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## SFR

Around here a kilowatt costs around 6 cents.  Think of a kilowatt as using a 100watt lightbulb for 10 hours.  Lets say an average computer uses around 50 watts an hour, so every day it uses 1.44 kilowatts.. so that is 8.64 cents a day.  so that will be around 259.2 cents every 30 days. So, every month keeping your computer on 24/7 will cost you 2 dollars and 59 cents (USD).

Thats a lot of money!


As for burning down a house.... I would be more concerned about leaving an overhead fan on....

geoff5093, as I said earlier, the most wear and tear happens when turning on and shutting off your computer.  and... after 11 years, if my PSU was the only thing malfunctioning in any of my computers, I would be very happy!


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## Gayble.com

SFR said:
			
		

> Around here a kilowatt costs around 6 cents.  Think of a kilowatt as using a 100watt lightbulb for 10 hours.  Lets say an average computer uses around 50 watts an hour, so every day it uses 1.44 kilowatts.. so that is 8.64 cents a day.  so that will be around 259.2 cents every 30 days. So, every month keeping your computer on 24/7 will cost you 2 dollars and 59 cents (USD).
> 
> Thats a lot of money!



$2.59 USD is alot of money?   That's extremely cheap IMO..


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## Yeti

> I've heard that the cooling system you use (fan, etc.) can also help with decreasing the electricity the computer uses..


Probably not.  One, your using more electricity to power the fan, and two, I doubt the PSU efficiency will increase much, if any, due to additional cooling, which would most likely need to be cooling directly on the PSU.

As for using more power on start up, there is a the inrush current, but unless you're turning the computer on and off every minute or so, that shouldn't be an issue.



> Around here a kilowatt costs around 6 cents


Wow, that's pretty cheap.  Here the average is a little under $0.12/kW-hr (even more for peak hours).  And technically electricity usage is measured in kilowatt-hrs (watt = Joule/sec so its already a rate).  



> Lets say an average computer uses around 50 watts


That's probably a pretty conservative value considering some processors can use in excess of 100 watts at full load.  Throw in the fans, hard drive(s), and a power hungry graphics card and you could use over a couple hundred watts.  So in conclusion, you could be (but not necessarily) paying around $10 a month (or more), or $120 a year just to keep your computer on.



> As for burning down a house.... I would be more concerned about leaving an overhead fan on....


Or forgetting to turn the stove of  ... well I didn't actually burn the house down, but I have forgotten to turn it off.


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## SFR

Yeti said:
			
		

> And technically electricity usage is measured in kilowatt-hrs (watt = Joule/sec so its already a rate).
> 
> That's probably a pretty conservative value considering some processors can use in excess of 100 watts at full load. Throw in the fans, hard drive(s), and a power hungry graphics card and you could use over a couple hundred watts. So in conclusion, you could be (but not necessarily) paying around $10 a month (or more), or $120 a year just to keep your computer on.


 
If you read my post again you will notice multiple places where I speak of watts and cost based on hours... 

What applications/games are you running that utilize 100% of your CPU? ..and if your CPU usage really goes to 100%... for how long?

anyway, the reason the word AVERAGE was in my statement is because any computer's CPU is not going to be processing at 100%, 24 hrs a day....

I would venture a guess that most of the day your CPU usage is near 0%.

So, in conclusion, I stand by my previous post


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## Yeti

> If you read my post again you will notice multiple places where I speak of watts and cost based on hours...
> 
> What applications/games are you running that utilize 100% of your CPU? ..and if your CPU usage really goes to 100%... for how long?
> 
> anyway, the reason the word AVERAGE was in my statement is because any computer's CPU is not going to be processing at 100%, 24 hrs a day....
> 
> I would venture a guess that most of the day your CPU usage is near 0%.
> 
> So, in conclusion, I stand by my previous post



I wasn’t trying to attack your calculations, just saying that they are probably more of a base value that could be higher.  

Also, don’t mean to be a prick but:


> Think of a kilowatt as using a 100watt lightbulb for 10 hours


That would be a kilowatt-hour, not a kilowatt.  A kilowatt is a unit of power, a kilowatt-hour is a unit of energy (its actually a Joule-hour/second, not quite as bad as the Btu/KW-hr heat rate rating, but still fairly stupid ).  


> Lets say an average computer uses around 50 watts an hour


It would be using 50 watts for one hour.


> so every day it uses 1.44 kilowatts.


It uses 1.44 kilowatt-hours.  Well, actually I think it would be 1.2 kW-hr (24 hr X 50 W X 1kW/1000 W)

As for the power consumption calculations:
1) 0% CPU usage does not mean no (or even very low) power consumption.  I’d say 20-30 W would be a conservative no load range.
2) My fans (case and HSF) alone take between 7.3 and 18.4 W depending on what my speed settings are (usually on the higher end).  
3) Idle hard drives, I have 4, total a bit over 20 W
4) I use my computer for a lot of encoding (really the only time the computer is on with me away from it is for encoding) which takes almost 100% of the CPU power.

There are other things that would consume additional power (gfx card, PSU, mobo, optical drives, etc).  I know that not everyone uses their computers like I do, or has the amount of components that I do, but I was trying to show that your value was on the low end.  Not trying to attack you, just trying to clarify .


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## Primex

*Turn your computer off or leave it on?*

I keep hearing different stories about how you should keep you computer on at all times, but then I read an article that stated that you should turn you computer off when it's not in use.  So which is it?  Should it be turned off when it's not in use or should it be left on?


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## dragon2309

Personal preference, it doesnt theoreticlly use that much electrivity, i mean a kettle uses more...... the only thing is that it might get "tired", as ni cache and temp files are massive cos they never get clerared out on BOOT. and you might not detect some problems if its never turned off, as they only show themselves on bootup.

Saying that, i leave my system on almost 24/7, gets sghut down and restarted at weekends when i do maintenance. It is a webserver thoguh.


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## Hairy_Lee

this thread is similar to yours http://www.computerforum.com/showthread.php?t=24539

it pretty much answers your question.


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## Geoff

They may not waste alot of electricity, but they do waste some, especially if its on 24/7.  The big thing is the life of your components, since each component only lasts for a certain number of hours, leaving it on all the time wears them down.  I would just put it in standby mode when your not using it, this way all you have to do is click and it comes back on instantly, and uses hardly any power.


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## Filip

i have my computer turned on 24/7 since i got my broadband connection 2 months ago, i dont have any problems, i have modified the registry so it clears my page file on every boot, on default it doesnt, it clears my cache as well, my computer is right next my bed, about 2 feet from my head when i sleep and i can bearly hear it, about the component life, i have an old duron 800 morgan core CPU, its  turned on around 20 hours a day an it still works, amazing CPU though


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## agashka

Ive got my pc just half feet from my bed , so me i gotta turn it off :/ or sleep on the couch cauz im too lazy to work for some noisless fans


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## Fuzz

I keep my computer on 24/7. I think turning your computer on and off alot will wear your parts out faster than leaving it on all the time.


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## Hairy_Lee

Fuzz said:
			
		

> I keep my computer on 24/7. I think turning your computer on and off alot will wear your parts out faster than leaving it on all the time.


 
thats gotta be the silliest thing i've ever heard. its actual use of a system that wears it out, so turning it off when you're not gonna use it is prolonging its life, aside from that it also saves electricity


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## Fuzz

The system board on a computer is full of solder points.  Given that, when a solder point is heated up and cooled down over and over again (such as turning on and off the computer) the solder becomes brittle and has more of a chance of breaking.


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## Hairy_Lee

how hot does your motherboard get? i'm an electrical engineer and i've worked on units that have soldered points that will get to 90 degrees easily and have yet to see this occur. if someone has told you this then they are either an idiot or are just trying to scare you


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## Fuzz

Ok, what does stuff do when it gets hot? It expands. What does stuff do when it gets cold? It contracts. You cant tell me by expanding and contracting something over and over agian will not make it brittle or broken more easily.

I also dont think you have to worry about life spans of parts such as harddrives the Western Digital Caviar is suppose to run for 1.2 million hours. That comes out to around 13888 years of use you can get out of it.

And yes I do see what youre saying, its not a serious problem. But you cant tell me what I said above isnt true.


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## Hairy_Lee

yeah, but how hot does it need to get to make a difference. also, lets just say your theory is infallable and this type of failure will happen on every computer (even though i haven't seen it on electrical equipment thats 20 years old).
how long do you plan on keeping your current system in its current configuration without changing anything, not even a change of modem. 2 years? 5 at a push?.... i think you see where i'm going with this and you will see that the saving of electricity will outweigh any so called life extension of your system, even though this type of failure will not occur.


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## Fuzz

Pretty much any failure that occurs could have been caused by the expanding and contracting of the solder points, such as a video card going bad, maybe it was caused by a loose connection which was caused by the expanding and contracting of the solder points. I think you and I are both right, it just depends on how you look at it.


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## Hairy_Lee

Fuzz said:
			
		

> Pretty much any failure that occurs could have been caused by the expanding and contracting, such as a video card going bad, maybe it was caused by a loose connection which was caused by the expanding and contracting of the solder joints. I think you and I are both right, it just depends on how you look at it.


 
i'm happy with that  

if high temps are encountered i would say that delamination of comonents would be a major issue but its pretty rare to have that occur


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## Fuzz

That was fun! And we didnt even have to resort to calling each other childish names.


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## The_Other_One

My view on this is that everything has a certain amount of time that it's made to run.  The more you run it, the more things wear out.  I'm mostly concerned about fans and harddrives, but the video card and processor(espcially with overclocked systems) could also be a consideration.

Now, I used to leave my system in suspend all the time, but for some reason it won't stay in that mode anymore.  But how my system would work, it would basically be completely off untill you pressed a button.  Then it would be right back where you left it.  No, not hibernation, suspend to ram as it's called in the bios.


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## Fuzz

As said before, I dont think you have to worry about life spans of parts such as harddrives the Western Digital Caviar is suppose to run for 1.2 million hours. That comes out to around 13888 years of use you can get out of it. Im sure most of the other brands run pretty close to it life span wise.


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## Geoff

It really just comes down to electricity, since computer components have very long life, they shouldnt die on you for many years.  So if you dont want to save electricity, then leave it on.


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## The_Other_One

Electric components have super long life spans.  Machanical devices have much shorter lifes.  Plus, don't beleive everything you read about the lifespan.  I've had drives die within a year, and I'm sure the lifespan was much longer considering they had a year warrenty!  I've also had servers(well, standard computers I ran all the time) that have died.  Caps started to bubble a bit in it so there might of been a heat problem, donno for sure, but it still died.


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## ceewi1

The_Other_One said:
			
		

> I've also had servers(well, standard computers I ran all the time) that have died.  Caps started to bubble a bit in it so there might of been a heat problem, donno for sure, but it still died.



If you're talking about the issue I think you're talking about, it was due to a series of faulty capacitors which were produced and sold to a number of major vendors. http://www.geek.com/news/geeknews/2003Feb/bch20030207018535.htm

The motherboards would have lasted longer if the caps hadn't been faulty.


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## The_Other_One

I doubt they were faulty, the computer was about 7 years old when it died...  But yeah, I know motherboards should last basically forever.


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## ericvonzipper

i know 2 families that turned theirs on and off every time they used it, yes used it, my friend upgraded theirs after 10yrs of this with NO failures, my aunt upgraded hers after 8 years, the hard drive failed, yep, her 8meg drive died.  I turn mine off every nite. The longest I've gone without an upgrade is 3yrs, if I have one last even 5 years it's probably time for an upgrade anyway.


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## ceewi1

I agree.  Computer components are unlikely to die before they become outdated and useless, unless they are faulty or abused, in which case it doesn't really matter whether the computer is left on or turned off.  I turn mine off to save power.


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## AdmnPower

i run processes in the middle of the night to back up my systems important files to my file server, and a run virus and spyware scans too. It's all very handy because i don't have to sit around and wait on it to get done. It also requires me to leave it on most of the time. I usually turn off my computer only when i want the quiet. Really though i think the only thing you may have to worry about is your power supply, i've had too many go bad to trust them to last very long in the long run.


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## Bobo

I leave my computer on 24/7, but I just reboot it like once a week.  Everything runs fine, and I have never had any problems with hardware.


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## JFlo

I do not care if i turn it off or leave it on.  If its on ill leave it on, mostly cause I would be to lazy to walk over there and turn it off.  How about your monitor? Does leaving on your monitor make a difference?  I usually shut it off even though i leave my computer on.


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## ceewi1

Yeh, I always turn off my monitor.  If you have a CRT monitor, it can be using as much power as the PC itself.  It also makes an unwanted light source if i'm not using the computer.  Mine's set to turn off after 20 mins anyway though.


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## krimson_king

Fuzz said:
			
		

> The system board on a computer is full of solder points.  Given that, when a solder point is heated up and cooled down over and over again (such as turning on and off the computer) the solder becomes brittle and has more of a chance of breaking.



um, unless youre playing football or something with it, i dont see any reason why something like that would matter.  it definitely makes sense to turn off your computer, mainly for mechanical purposes.


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## Motoxrdude

Like everyone else said, it doesnt matter too much what you do, leave it on or off. I usually restart my computer about every 3 days because my ram just gets fuller and fuller, so i start noticing lag when doing simple tasks. My home server has been on for 3 years straight. I have a 120min battery back up for it so it hasnt ever been turned off and it runs great.


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## hello45044

Ive got tons of stuff on my computer, so it needs tons of fans to keep it cool. I'm too lazy to get a better case or round ide cables or something. I just add more fans. My computer sounds like a helicopter, so I put it in sleep mode when I'm not using it.


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## Veurruckte

Many people brag about their uptime, which I believe is stupid. Unless you're serving, I would say shut it down (Especially running windows). Your components will last longer, and you will be saving power  .

You can always find a use for old machines. One example would be using it as a firewall.


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## DaShit

the part that is prolly going to go out first because leaving it on 24/7 would be the PSU, they only have lifes of like 100,000 hrs which is like 3 years


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## ericvonzipper

I've had 2 pwr supplies go after the 5 yr mark, I started to doubt the quality from the computer store I got them from but they said 3-5 yrs is the expected life. $20 powersupply, guess I got my monies worth.


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## Bobo

I am still using power suppllies that are over 10 years old, they are second, third, fourth hand and they work fine


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## Praetor

> Ok, what does stuff do when it gets hot? It expands. What does stuff do when it gets cold? It contracts.


How about water from -4C to 0C? 

*threads merged*


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