Does power saver actually help?

Does the power saver function actually help save power? I’ve heard with some mp3 players that it’s better to just leave the player on than to power it off and then back on when not in use because it uses more power to power on the device than if you were to just leave it on. I dk if that’s true or not, I’ve never really done any research on the subject. Was just wondering if anyone here may know the answer to that.

Power saver does save power with any reasonable setting. I think mine is set at 20 minutes. You should pick a reasonable setting so the player won’t be in standby for long periods of time, but not such a short setting that you need to boot it many times a day.

@jman831 wrote:
Does the power saver function actually help save power? I’ve heard with some mp3 players that it’s better to just leave the player on than to power it off and then back on when not in use because it uses more power to power on the device than if you were to just leave it on. I dk if that’s true or not, I’ve never really done any research on the subject. Was just wondering if anyone here may know the answer to that.

That’s an old wive’s tale and pertains only to AC electrical, plugged-in devices like lights, TV, etc. This has also been proven to be false. Somebody apparently thought it would be a good idea to bring this old chestnut into the 21st century by saying it’s applicable to battery-powered thing-a-ma-bobs like mp3 players, but obviously didn’t know what they are talking about.

Here’s a little tidbit that _ is _ correct . . . just because you read it on the internet, doesn’t make it true.

@tapeworm wrote:


@jman831 wrote:
Does the power saver function actually help save power? I’ve heard with some mp3 players that it’s better to just leave the player on than to power it off and then back on when not in use because it uses more power to power on the device than if you were to just leave it on. I dk if that’s true or not, I’ve never really done any research on the subject. Was just wondering if anyone here may know the answer to that.


That’s an old wive’s tale and pertains only to AC electrical, plugged-in devices like lights, TV, etc. This has also been proven to be false. Somebody apparently thought it would be a good idea to bring this old chestnut into the 21st century by saying it’s applicable to battery-powered thing-a-ma-bobs like mp3 players, but obviously didn’t know what they are talking about.

 

Here’s a little tidbit that _ is _ correct . . . just because you read it on the internet, doesn’t make it true.

Though I do agree with you that just because it’s on the internet doesn’t mean it’s true, where exactly did you get this information that proves it is false? Did they do it on mythbusters or something?

@jman831 wrote:


Though I do agree with you that just because it’s on the internet doesn’t mean it’s true, where exactly did you get this information that proves it is false? Did they do it on mythbusters or something?

I don’t know if its been proven false (would be hard I think to test it for every possible device out there), but it absolutely is false because it makes no sense at all.  Leaving things on dates back to vaccuum tubes which have to be heated up to relatively high temperatures to function.  If you did that a lot they’d fail sooner due to glass cracking and seals failing.  Theres no vaccuum tubes in your mp3 player, its made out of transistors like most stuff since the 1970s.  Those function at room temperature and thus don’t have thermal cycling quite like vaccuum tubes.

There is a grain of truth in it, as some modern items do consume a bit  more power when first turned on, however even if power consumption doubles for half a minute or a minute(doubling is a very an extreme case), it makes sense to turn things off to save power. Turning things on though does put extra stress on the circuitry(and wear on the switch), so to make things last longer it makes sense not to turn things on and off many times a day. I usually turn on my pc once or twice a day. Some may turn theirs on many times a day, while others leave theirs on all the time.

@jman831 wrote:

Though I do agree with you that just because it’s on the internet doesn’t mean it’s true, where exactly did you get this information that proves it is false? Did they do it on mythbusters or something?

Mythbusters did do a segment on whether light bulbs consume more power if turned off when not needed vs. left on all the time. They found that there IS  a spike in current when it’s first turned on, but it’s so brief (a fraction of a second) that it isn’t nearly enough to validate leaving the lights on to avoid the spike. To my knowledge they’ve never tested the same theory on portable electronics, but I strongly suspect the findings would be the same.

@gwk1967 wrote:

 They found that there IS  a spike in current when it’s first turned on, but it’s so brief (a fraction of a second) that it isn’t nearly enough to validate leaving the lights on to avoid the spike. To my knowledge they’ve never tested the same theory on portable electronics, but I strongly suspect the findings would be the same.

Thats because you have to wait for the wire to heat up before the filament will reach its normal resistance.  Once its heated up the resistance increases and the power use drops.  Theres no such spike when you turn on most battery powered electronics (well beyond the normal power spike whenever you turn on the screen).  

I took some measurements a while ago while doing powermanagement stuff for rockbox on the e200:

http://duke.edu/~mgg6/rockbox/30mhz-2.png

http://duke.edu/~mgg6/rockbox/80mhz-2.png

You can see the power usage basically just depends on what is powered up, but doesn’t vary over time unless something else is powered on.  Thats because these low power transistor based circuits don’t heat up and have carefully regulated supply voltages.  

saratoga wrote


I don’t know if its been proven false (would be hard I think to test it for every possible device out there), but it absolutely is false because it makes no sense at all.  Leaving things on dates back to vaccuum tubes which have to be heated up to relatively high temperatures to function.  If you did that a lot they’d fail sooner due to glass cracking and seals failing.  Theres no vaccuum tubes in your mp3 player, its made out of transistors like most stuff since the 1970s.  Those function at room temperature and thus don’t have thermal cycling quite like vaccuum tubes.

 

I can see what you’re saying about vaccuum tubes because I could see that making a big difference. If powering it on wouldn’t be much different than bringing up the screen, wouldn’t that mean it’d use just as much battery power to leave it on with the screen off as turning it off and turning it back on? Or would the fact that it has to keep a memory of your last action use power as well?

@jman831 wrote:

 If powering it on wouldn’t be much different than bringing up the screen, wouldn’t that mean it’d use just as much battery power to leave it on with the screen off as turning it off and turning it back on?

No, it does not follow that because screens use a lot of power, processors do not need power.  In fact, the CPU on your mp3 player ends up dominating power use.

Edit:  You might be interested in the charts I posted above your post.  They show power usage as the CPU does things.