I have seen various discussions about whether or not money or power is saved
depending on turning the computer off periodically as opposed to just leaving
it on all the time.
Obviously it will use less power when off. My question concerns how this
practice affects the lifespan of the hardware. I know that in any
electronic device, when first powered up, there is an "inrush current"
required to charge capacitors (such as filter capacitors in the various power
supplies). Has there been any studies to determine the optimum on-off rate?
In other words, if it is only turned on once a day and off at night, is this
better than turning it on and off say 4 or 6 time in a 24 hour period? Any
discussion along this line would be helpful.

"eingram" <(E-Mail Removed)> wrote in message
news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
>I have seen various discussions about whether or not money or power is
>saved
> depending on turning the computer off periodically as opposed to just
> leaving
> it on all the time.
> Obviously it will use less power when off. My question concerns how this
> practice affects the lifespan of the hardware. I know that in any
> electronic device, when first powered up, there is an "inrush current"
> required to charge capacitors (such as filter capacitors in the various
> power
> supplies). Has there been any studies to determine the optimum on-off
> rate?
> In other words, if it is only turned on once a day and off at night, is
> this
> better than turning it on and off say 4 or 6 time in a 24 hour period?
> Any
> discussion along this line would be helpful.

All the hardware related discussions I've read revolved around current use
by hard drive turn-on, not the PC itself as far as life expectancy. This
also occurs when waking from hibernation as the hard drives are powered down
during hibernation. Does not occur in standby.

I still have, as other people do, a PC a decade old with an AT power supply.
When I use it, I turn it on first. When I'm done, I turn it off. There is
no hibernate or standby use. It still works. I don't need a study to
figure out what that means, that is, what someone else deduces about that.
How it would compare if I setup the bios or the OS to use standby doesn't
matter. If it ain't broke, don't fix it.
Dave

I don't know about studies, but I did spend a few years in the labs of a
major US-based TV manufacturer some time back, and we used to run long term
life tests where sets were both run continuously and power was cycled. The
cycled sets failed sooner. The reason was thermal expansion and contraction.
The parts in any electric device will expand and contract as they heat and
cool. They will, naturally, expand and contract more if the thermal cycles
are more extreme.

In an office environment the best choice for users' systems seems to be turn
it on in the morning and turn it off when you leave. That's only two thermal
cycles a day, and lots of energy saved. A good balance. At home, we're not
talking about lots of PCs and lots of power, so energy isn't much of an
issue, unless you're running a green home. This is a wild guess, but
toasting a bagel uses the same amount of power your PC consumes in a day or
two. (Someone can figure this out, i'm too lazy.)

-John O


"eingram" <(E-Mail Removed)> wrote in message
news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
>I have seen various discussions about whether or not money or power is
>saved
> depending on turning the computer off periodically as opposed to just
> leaving
> it on all the time.
> Obviously it will use less power when off. My question concerns how this
> practice affects the lifespan of the hardware. I know that in any
> electronic device, when first powered up, there is an "inrush current"
> required to charge capacitors (such as filter capacitors in the various
> power
> supplies). Has there been any studies to determine the optimum on-off
> rate?
> In other words, if it is only turned on once a day and off at night, is
> this
> better than turning it on and off say 4 or 6 time in a 24 hour period?
> Any
> discussion along this line would be helpful.

John

Your comments on thermal expansion and contraction are interesting. I
suspect there have been studies on the light bulb illustrating what you
say.

Doesn't obsolesence occur before many computer components cease to be
functional?

Leaving computers on also have an effect on system performance with
regard to programmes with memory leaks not releasing memory.

--
Regards.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~


JohnO wrote:
> I don't know about studies, but I did spend a few years in the labs
> of a major US-based TV manufacturer some time back, and we used to
> run long term life tests where sets were both run continuously and
> power was cycled. The cycled sets failed sooner. The reason was
> thermal expansion and contraction. The parts in any electric device
> will expand and contract as they heat and cool. They will, naturally,
> expand and contract more if the thermal cycles are more extreme.
>
> In an office environment the best choice for users' systems seems to
> be turn it on in the morning and turn it off when you leave. That's
> only two thermal cycles a day, and lots of energy saved. A good
> balance. At home, we're not talking about lots of PCs and lots of
> power, so energy isn't much of an issue, unless you're running a
> green home. This is a wild guess, but toasting a bagel uses the same
> amount of power your PC consumes in a day or two. (Someone can figure
> this out, i'm too lazy.)
> -John O
>
>
> "eingram" <(E-Mail Removed)> wrote in message
> news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
>> I have seen various discussions about whether or not money or power
>> is saved
>> depending on turning the computer off periodically as opposed to just
>> leaving
>> it on all the time.
>> Obviously it will use less power when off. My question concerns how
>> this practice affects the lifespan of the hardware. I know that in
>> any electronic device, when first powered up, there is an "inrush
>> current" required to charge capacitors (such as filter capacitors in
>> the various power
>> supplies). Has there been any studies to determine the optimum
>> on-off rate?
>> In other words, if it is only turned on once a day and off at night,
>> is this
>> better than turning it on and off say 4 or 6 time in a 24 hour
>> period? Any
>> discussion along this line would be helpful.

Just use standby if you are concerned about this.

eingram wrote:

> I have seen various discussions about whether or not money or power is saved
> depending on turning the computer off periodically as opposed to just leaving
> it on all the time.
> Obviously it will use less power when off. My question concerns how this
> practice affects the lifespan of the hardware. I know that in any
> electronic device, when first powered up, there is an "inrush current"
> required to charge capacitors (such as filter capacitors in the various power
> supplies). Has there been any studies to determine the optimum on-off rate?
> In other words, if it is only turned on once a day and off at night, is this
> better than turning it on and off say 4 or 6 time in a 24 hour period? Any
> discussion along this line would be helpful.

I'm sure many companies have studied their own products, but a lot of that
data is proprietary and we won't get to see it, unfortunately. Such a test
is pretty easy, you need one of those timer-type AC switches
(http://tinyurl.com/2jh3ag) from Walmart and a control device that is left
on continuously. And a few weeks. As far as TVs are concerned, they
accelerated the tests by increasing the line voltage to 132 VAC and the
set's B+ (high voltage source) by 25% or something like that. Also, they
jacked up the ambient temp in the room to about 85 F, sometimes a lot higher
if there was a hurry.

-John O


> John
>
> Your comments on thermal expansion and contraction are interesting. I
> suspect there have been studies on the light bulb illustrating what you
> say.
>
> Doesn't obsolesence occur before many computer components cease to be
> functional?
>
> Leaving computers on also have an effect on system performance with regard
> to programmes with memory leaks not releasing memory.
>
> --
> Regards.
>
> Gerry
> ~~~~
> FCA
> Stourport, England
> Enquire, plan and execute
> ~~~~~~~~~~~~~~~~~~~
>
>
> JohnO wrote:
>> I don't know about studies, but I did spend a few years in the labs
>> of a major US-based TV manufacturer some time back, and we used to
>> run long term life tests where sets were both run continuously and
>> power was cycled. The cycled sets failed sooner. The reason was
>> thermal expansion and contraction. The parts in any electric device
>> will expand and contract as they heat and cool. They will, naturally,
>> expand and contract more if the thermal cycles are more extreme.
>>
>> In an office environment the best choice for users' systems seems to
>> be turn it on in the morning and turn it off when you leave. That's
>> only two thermal cycles a day, and lots of energy saved. A good
>> balance. At home, we're not talking about lots of PCs and lots of
>> power, so energy isn't much of an issue, unless you're running a
>> green home. This is a wild guess, but toasting a bagel uses the same
>> amount of power your PC consumes in a day or two. (Someone can figure
>> this out, i'm too lazy.)
>> -John O
>>
>>
>> "eingram" <(E-Mail Removed)> wrote in message
>> news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
>>> I have seen various discussions about whether or not money or power
>>> is saved
>>> depending on turning the computer off periodically as opposed to just
>>> leaving
>>> it on all the time.
>>> Obviously it will use less power when off. My question concerns how
>>> this practice affects the lifespan of the hardware. I know that in
>>> any electronic device, when first powered up, there is an "inrush
>>> current" required to charge capacitors (such as filter capacitors in
>>> the various power
>>> supplies). Has there been any studies to determine the optimum
>>> on-off rate?
>>> In other words, if it is only turned on once a day and off at night,
>>> is this
>>> better than turning it on and off say 4 or 6 time in a 24 hour
>>> period? Any
>>> discussion along this line would be helpful.
>
>

John

Thanks John but that's way over my head.


--
Regards.

Gerry
~~~~
FCA
Stourport, England
Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~
JohnO wrote:
> I'm sure many companies have studied their own products, but a lot of
> that data is proprietary and we won't get to see it, unfortunately.
> Such a test is pretty easy, you need one of those timer-type AC
> switches (http://tinyurl.com/2jh3ag) from Walmart and a control
> device that is left on continuously. And a few weeks. As far as TVs
> are concerned, they accelerated the tests by increasing the line
> voltage to 132 VAC and the set's B+ (high voltage source) by 25% or
> something like that. Also, they jacked up the ambient temp in the
> room to about 85 F, sometimes a lot higher if there was a hurry.
>
> -John O
>
>
>> John
>>
>> Your comments on thermal expansion and contraction are interesting. I
>> suspect there have been studies on the light bulb illustrating what
>> you say.
>>
>> Doesn't obsolesence occur before many computer components cease to be
>> functional?
>>
>> Leaving computers on also have an effect on system performance with
>> regard to programmes with memory leaks not releasing memory.
>>
>> --
>> Regards.
>>
>> Gerry
>> ~~~~
>> FCA
>> Stourport, England
>> Enquire, plan and execute
>> ~~~~~~~~~~~~~~~~~~~
>>
>>
>> JohnO wrote:
>>> I don't know about studies, but I did spend a few years in the labs
>>> of a major US-based TV manufacturer some time back, and we used to
>>> run long term life tests where sets were both run continuously and
>>> power was cycled. The cycled sets failed sooner. The reason was
>>> thermal expansion and contraction. The parts in any electric device
>>> will expand and contract as they heat and cool. They will,
>>> naturally, expand and contract more if the thermal cycles are more
>>> extreme. In an office environment the best choice for users' systems
>>> seems to
>>> be turn it on in the morning and turn it off when you leave. That's
>>> only two thermal cycles a day, and lots of energy saved. A good
>>> balance. At home, we're not talking about lots of PCs and lots of
>>> power, so energy isn't much of an issue, unless you're running a
>>> green home. This is a wild guess, but toasting a bagel uses the same
>>> amount of power your PC consumes in a day or two. (Someone can
>>> figure this out, i'm too lazy.)
>>> -John O
>>>
>>>
>>> "eingram" <(E-Mail Removed)> wrote in message
>>> news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
>>>> I have seen various discussions about whether or not money or power
>>>> is saved
>>>> depending on turning the computer off periodically as opposed to
>>>> just leaving
>>>> it on all the time.
>>>> Obviously it will use less power when off. My question concerns
>>>> how this practice affects the lifespan of the hardware. I know
>>>> that in any electronic device, when first powered up, there is an
>>>> "inrush current" required to charge capacitors (such as filter
>>>> capacitors in the various power
>>>> supplies). Has there been any studies to determine the optimum
>>>> on-off rate?
>>>> In other words, if it is only turned on once a day and off at
>>>> night, is this
>>>> better than turning it on and off say 4 or 6 time in a 24 hour
>>>> period? Any
>>>> discussion along this line would be helpful.

Incorrect calculation: Assume S3, hibernation, or off are all about the
same energy drain (< 5 watts). Assume on usage power is about 175 Watts,
off time is weekends + 12 hours per day. With these assumptions, the
value of turning the computer off (or hibernating or using S3 suspend)
is 1 MEGA WATT HOUR PER YEAR. Look at your electric bill for rates and I
think you will find this saves hundreds of dollars per year per
computer. Your bagel toasting, while more taste-enhancing than
computation, is rather inexpensive in comparison to a few days extra up
time.

-- Jeff Barnett


JohnO wrote:
> I don't know about studies, but I did spend a few years in the labs of a
> major US-based TV manufacturer some time back, and we used to run long term
> life tests where sets were both run continuously and power was cycled. The
> cycled sets failed sooner. The reason was thermal expansion and contraction.
> The parts in any electric device will expand and contract as they heat and
> cool. They will, naturally, expand and contract more if the thermal cycles
> are more extreme.
>
> In an office environment the best choice for users' systems seems to be turn
> it on in the morning and turn it off when you leave. That's only two thermal
> cycles a day, and lots of energy saved. A good balance. At home, we're not
> talking about lots of PCs and lots of power, so energy isn't much of an
> issue, unless you're running a green home. This is a wild guess, but
> toasting a bagel uses the same amount of power your PC consumes in a day or
> two. (Someone can figure this out, i'm too lazy.)
>
> -John O
>
>
> "eingram" <(E-Mail Removed)> wrote in message
> news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
>
>> I have seen various discussions about whether or not money or power is
>> saved
>> depending on turning the computer off periodically as opposed to just
>> leaving
>> it on all the time.
>> Obviously it will use less power when off. My question concerns how this
>> practice affects the lifespan of the hardware. I know that in any
>> electronic device, when first powered up, there is an "inrush current"
>> required to charge capacitors (such as filter capacitors in the various
>> power
>> supplies). Has there been any studies to determine the optimum on-off
>> rate?
>> In other words, if it is only turned on once a day and off at night, is
>> this
>> better than turning it on and off say 4 or 6 time in a 24 hour period?
>> Any
>> discussion along this line would be helpful.
>>
>
>
>

Well, I'm not confident that a home computer uses a lot of energy,
relatively speaking. The toaster may have been a poor example, it's a lot of
power and carbs but not much time.

http://ets.fhda.edu/call_center/greencomputing

A university site says basically the same thing:

"How a user operates the computer also factors into energy costs. First let's
take the worst case scenario, continuous operation. Assuming you operate a
200 watt PC system day and night everyday, direct annual electrical costs
would be over $125 (at $0.075/kWh). In contrast, if you operate your system
just during normal business hours, say 40 hours per week, the direct annual
energy cost would be about $30 - plus, of course, the cost of providing
additional cooling."

Consider the 40 hours a bit high, then consider most of our computers draw
*a lot* less than 200 watts, and the electric costs are pretty low in each
home.

I have an electric stove, microwave, air conditioning, pool filter, water
heater, dehumidifier, coffeemaker, and clothes dryer. Computer electrical
costs are way down on the "worry" list for me.

Here's another good and very basic discussion:
http://www.humboldt.edu/~mrd26/home_energy.htm

-John O


"Jeff Barnett" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> Incorrect calculation: Assume S3, hibernation, or off are all about the
> same energy drain (< 5 watts). Assume on usage power is about 175 Watts,
> off time is weekends + 12 hours per day. With these assumptions, the value
> of turning the computer off (or hibernating or using S3 suspend) is 1 MEGA
> WATT HOUR PER YEAR. Look at your electric bill for rates and I think you
> will find this saves hundreds of dollars per year per computer. Your bagel
> toasting, while more taste-enhancing than computation, is rather
> inexpensive in comparison to a few days extra up time.
>
> -- Jeff Barnett
>
>
> JohnO wrote:
>> I don't know about studies, but I did spend a few years in the labs of a
>> major US-based TV manufacturer some time back, and we used to run long
>> term life tests where sets were both run continuously and power was
>> cycled. The cycled sets failed sooner. The reason was thermal expansion
>> and contraction. The parts in any electric device will expand and
>> contract as they heat and cool. They will, naturally, expand and contract
>> more if the thermal cycles are more extreme.
>>
>> In an office environment the best choice for users' systems seems to be
>> turn it on in the morning and turn it off when you leave. That's only two
>> thermal cycles a day, and lots of energy saved. A good balance. At home,
>> we're not talking about lots of PCs and lots of power, so energy isn't
>> much of an issue, unless you're running a green home. This is a wild
>> guess, but toasting a bagel uses the same amount of power your PC
>> consumes in a day or two. (Someone can figure this out, i'm too lazy.)

"eingram" <(E-Mail Removed)> wrote in message
news:B3772D7D-C491-4C11-AD8E-(E-Mail Removed)...
> I have seen various discussions about whether or not money or power is
saved
> depending on turning the computer off periodically as opposed to just
leaving
> it on all the time.
> Obviously it will use less power when off. My question concerns how this
> practice affects the lifespan of the hardware. I know that in any
> electronic device, when first powered up, there is an "inrush current"
> required to charge capacitors (such as filter capacitors in the various
power
> supplies). Has there been any studies to determine the optimum on-off
rate?
> In other words, if it is only turned on once a day and off at night, is
this
> better than turning it on and off say 4 or 6 time in a 24 hour period?
Any
> discussion along this line would be helpful.


Although there is some stress on components during power-up...
it's best to turn the machine off when not in use (unless you are going to
get back to it shortly)


Here is *one* story, though there are many:

A few years back I built a machine for a professional photographer
who had a lot of data he needed to keep avail.
That was back before there were 1TB drives...so his machine had at least 5
or 6 drives total...
and he kept the machine on 24/7

I have never seen so many HD failures in my life...
I think that sooner or later they all died (and were replaced)


I advised him to keep the machine on only when in use...
he never lost a drive again...

that was quite a few years ago.