RAM draws a small amount of power to "remember" what is stored in its cells (which are capacitors in DRAM that discharge quickly - so they have to be refreshed constantly). However, there are no moving parts.
A hard disk, on the other hand, is one or more gigantic (from a circuit's point of view) physical platters that have to be accelerated up to a high speed, kept there, and accessed by physically moving immense (to a circuit) arms. The amount of current required to spin up and power a moving device of considerable size dwarfs the amount of current required to keep a bunch of tiny capacitors full with a very small charge.
If you really want to save battery life, stuff as much RAM as you can manage to into your laptop. No matter how much of it there is it will be markedly more power efficient than a busy hard drive. OS X will be better able to use it, as well, since it not only uses the hard drive for virtual memory, it uses RAM as a virtual hard drive (i.e., it caches recently accessed files in memory).
Resetting the PMU didn't work. My iBook's 1.5 years old, the store told me the battery was dead. Is it or are they just trying to sell me a $139 battery?
I have a TiBook 1 GHz Superdrive 1 GB RAM. I got it in Nov. About two weeks or so after they were available. For the past 2 weeks I've been discharging my battery through everyday use, and recharging and so forth. My energy saver settings are set to automatic, with processor performance set to reduced. My display brightness settings are about 4 notches down. I still only only get about 2.5 hours, sometimes it jumps to 3 but then readily lowers itself to about 2:45 minutes. The most I've been able to squeeze out of it by doing the discharge thing. I even timed it with a watch and it is the same time.
Is my battery not operating properly? I've been doing some research and some people on macnn get about 2.5 hours while others get 4-5 hrs (these are 867/1Ghz Tibook owners). I have Applecare, will Apple replace my battery? I mean it is functioning properly but it just doesn't hold a charge as well as most other batteries. I guess I will try reseting the PMU, but I don't think it will do a difference.
<strong>My display brightness settings are about 4 notches down. I still only only get about 2.5 hours, sometimes it jumps to 3 but then readily lowers itself to about 2:45 minutes.</strong><hr></blockquote>
Try lowering your display brightness further. Assuming all GHz TiBook displays are roughly comparable, you should be able to reduce it to 5 notches or so and still get a good enough picture. This, in my experience, makes a big difference in battery life.
<strong>I have a TiBook 1 GHz Superdrive 1 GB RAM. I got it in Nov. About two weeks or so after they were available. For the past 2 weeks I've been discharging my battery through everyday use, and recharging and so forth. My energy saver settings are set to automatic, with processor performance set to reduced. My display brightness settings are about 4 notches down. I still only only get about 2.5 hours, sometimes it jumps to 3 but then readily lowers itself to about 2:45 minutes. The most I've been able to squeeze out of it by doing the discharge thing. I even timed it with a watch and it is the same time.
Is my battery not operating properly? I've been doing some research and some people on macnn get about 2.5 hours while others get 4-5 hrs (these are 867/1Ghz Tibook owners). I have Applecare, will Apple replace my battery? I mean it is functioning properly but it just doesn't hold a charge as well as most other batteries. I guess I will try reseting the PMU, but I don't think it will do a difference.
any help will be appreciated.
thanks</strong><hr></blockquote>
Are you using Airport?
Airport (and all 802.11 implementation) uses a lot of power.
On the subject of Energy Saver, this is something I read at another place:
[quote]This weekend I was installing CHUD (packaged with Developer Tools) on my brand new, just out of the box, 1Ghz PowerBook. When I went to use the CPU preference pane, I notice the 1mb L3 cache was not enabled. I tried to enable it but it wouldn't. I then downloaded SpeedRun and saw my benchmark numbers where lower than a 500Mhz G4. Something wasn't right?It appears that Apple disables the L3 cache as part of its Energy Saving process on PowerBooks (perhaps iBooks as well). <hr></blockquote>
I tried the PMU reset and lowered my display brightness to about half. Airport is also off. the battery got a little better around 3 hrs. Nothing like what I hear other people are getting. I am going to keep discharging the battery and recharging for a couple of more days and if it still displays 3 hrs I will send the battery back to Apple.
One thing I've noticed is a spurious "You are now on reserve power, please plug in your PowerBook soon" message when waking from sleep. The power use in the few short seconds after opening the lid (Pismo PowerBook, 3+ yrs old, original battery) is enough that it fools the power management into thinking "Well heck, at *this* rate we're going to drain the sucker in just a couple of minutes!" and up pops the erroneous dialog.
It's harmless, but annoying when the battery shows 70% full, and it tells me it's about to run out.
Comments
A hard disk, on the other hand, is one or more gigantic (from a circuit's point of view) physical platters that have to be accelerated up to a high speed, kept there, and accessed by physically moving immense (to a circuit) arms. The amount of current required to spin up and power a moving device of considerable size dwarfs the amount of current required to keep a bunch of tiny capacitors full with a very small charge.
If you really want to save battery life, stuff as much RAM as you can manage to into your laptop. No matter how much of it there is it will be markedly more power efficient than a busy hard drive. OS X will be better able to use it, as well, since it not only uses the hard drive for virtual memory, it uses RAM as a virtual hard drive (i.e., it caches recently accessed files in memory).
[ 01-03-2003: Message edited by: Amorph ]</p>
Is my battery not operating properly? I've been doing some research and some people on macnn get about 2.5 hours while others get 4-5 hrs (these are 867/1Ghz Tibook owners). I have Applecare, will Apple replace my battery? I mean it is functioning properly but it just doesn't hold a charge as well as most other batteries. I guess I will try reseting the PMU, but I don't think it will do a difference.
any help will be appreciated.
thanks
<strong>My display brightness settings are about 4 notches down. I still only only get about 2.5 hours, sometimes it jumps to 3 but then readily lowers itself to about 2:45 minutes.</strong><hr></blockquote>
Try lowering your display brightness further. Assuming all GHz TiBook displays are roughly comparable, you should be able to reduce it to 5 notches or so and still get a good enough picture. This, in my experience, makes a big difference in battery life.
Bye,
RazzFazz
<strong>I have a TiBook 1 GHz Superdrive 1 GB RAM. I got it in Nov. About two weeks or so after they were available. For the past 2 weeks I've been discharging my battery through everyday use, and recharging and so forth. My energy saver settings are set to automatic, with processor performance set to reduced. My display brightness settings are about 4 notches down. I still only only get about 2.5 hours, sometimes it jumps to 3 but then readily lowers itself to about 2:45 minutes. The most I've been able to squeeze out of it by doing the discharge thing. I even timed it with a watch and it is the same time.
Is my battery not operating properly? I've been doing some research and some people on macnn get about 2.5 hours while others get 4-5 hrs (these are 867/1Ghz Tibook owners). I have Applecare, will Apple replace my battery? I mean it is functioning properly but it just doesn't hold a charge as well as most other batteries. I guess I will try reseting the PMU, but I don't think it will do a difference.
any help will be appreciated.
thanks</strong><hr></blockquote>
Are you using Airport?
Airport (and all 802.11 implementation) uses a lot of power.
[quote]This weekend I was installing CHUD (packaged with Developer Tools) on my brand new, just out of the box, 1Ghz PowerBook. When I went to use the CPU preference pane, I notice the 1mb L3 cache was not enabled. I tried to enable it but it wouldn't. I then downloaded SpeedRun and saw my benchmark numbers where lower than a 500Mhz G4. Something wasn't right?It appears that Apple disables the L3 cache as part of its Energy Saving process on PowerBooks (perhaps iBooks as well). <hr></blockquote>
You can read the full (short) article <a href="http://www.macosxhints.com/article.php?story=20030103064631426#comments"; target="_blank">here.</a>
thanks for all your help.
happy new year everyone!
It's harmless, but annoying when the battery shows 70% full, and it tells me it's about to run out.