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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Notebooks > how do the new powerbooks have better battery life?

how do the new powerbooks have better battery life?
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brent0saurus
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Oct 26, 2005, 04:18 PM
 
How do the newer powerbooks have better battery life? Is it a better battery or a different chipset what? I read at AppleInsider that the new powerbooks are shipping with a new build of 10.4.2 known as 8E45. What does that mean and could that be the reason they have better battery life? So maybe 10.4.3 will improve my powerbook's battery life?? *wishful thinking*
     
Fusion
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Oct 26, 2005, 04:37 PM
 
1. The screens are more energy efficient.

2. The new RAM runs at less power.

3. As you mentioned, the special build of 10.4.2 uses a special stepping technique. The processor controls are gone now. So the whole OS has just been optimized better.

4. A bigger capacity battery. 50 compared to 44 I believe.
     
tooki
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Oct 26, 2005, 04:55 PM
 
The batteries are unchanged.

I've seen no evidence that the screens are "more energy efficient". I think this is rather unlikely, since fluorescent tube technology has been around for almost 90 years, pretty much unchanged. It's about as efficient as it's gonna get.

The RAM is a minor component, but the big ones that Apple has announced are much-improved speed stepping on the CPU and GPU (taken from the 17", but it's the same on the 15"):
Processor Power Management
To lower power consumption and heat generation, the 17-inch PowerBook G4 incorporates an automatic power management stepping technique. Stepping is designed to run at full, half, or quarter processor speed and voltage to meet the demands on the processor. The processor speed will switch between 1670 MHz and 833 MHz at 1.30 V for divide by 2 and between 1670 MHz and 417 MHz at .93 V for divide by 4. The memory bus speed is not shifted.

If the 17-inch PowerBook G4 detects a system temperature that is high, due to high ambient temperatures or other factors, it will immediately force the system to quarter speed mode.

The 17-inch PowerBook G4 meets all applicable safety standards, including UL 60950 and IEC 60950.

Graphics Power Management
For additional power savings and reduced heat generation, the 17-inch PowerBook G4 incorporates a dynamic graphics power management technique. When required, the graphics processor runs at a reduced voltage and slower clock rate, similar to stepping on the central processor.
Compare this with the same sections from the developer notes from the previous version:
Processor Power Management
To lower power consumption and heat generation, the 17-inch PowerBook G4 incorporates an automatic power management technique called dynamic frequency switching (DFS). DFS is designed to run at high processor speed and voltage when the demand on the processor is high, and to run at low processor speed and voltage when the demand on the processor is low. When DFS is enabled, the processor dynamically adjusts its speed based on the current needs of the system. The processor speed will switch between 1670 MHz and 835 MHz. The memory bus speed is not shifted, as it was in previous models.

Switching between different processor speeds and voltages is achieved by a transition that should operate seamlessly to the user. For applications that are particulary demanding on the processor, it is recommended that the processor performance be set to highest.

The 17-inch PowerBook G4 allows the user to control DFS mode. The options for specifying either high, reduced, or automatic processor speeds are located at System Preferences>Energy Saver>Show Details>Options>Processor Performance; then select Highest, Automatic, or Reduced. DFS is enabled with the automatic setting.

If the 17-inch PowerBook G4 detects a system temperature that is high, due to high ambient temperatures or other factors, it will automatically force the system to reduced speed mode regardless of the selected setting.

The 17-inch PowerBook G4 meets all applicable safety standards, including UL 60950 and IEC 60950.

Graphics Power Management
For additional power savings and reduced heat generation, the 17-inch PowerBook G4 incorporates a new graphics power management technique. When enabled, the graphics processor runs at a reduced voltage and slower clock rate, similar to DFS on the central processor. However, unlike DFS, the setting is static and does not automatically change as the load on the graphics processor changes.

Graphics power management is enabled by selecting reduced mode located at System Preferences>Energy Saver>Show Details> Options>Processor Perfomance.
Reportedly, the motherboard chipset in the new models also supports better power management.

tooki
     
a2daj
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Oct 26, 2005, 07:17 PM
 
I picked up a new 15" PB last night and I noticed that there's no longer a Performance drop down menu in System Preferences>Energy Saver>Show Details> Options. So it seems that my new PB will always be set to Automatic.
     
mduell
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Oct 26, 2005, 07:24 PM
 
Originally Posted by tooki
I've seen no evidence that the screens are "more energy efficient". I think this is rather unlikely, since fluorescent tube technology has been around for almost 90 years, pretty much unchanged. It's about as efficient as it's gonna get.
The new 17" screens are brighter, so they may even consume more power.
     
brent0saurus  (op)
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Oct 26, 2005, 09:49 PM
 
so do you think that 10.4.3 will improve battery life? I don't understand what speed stepping is exactly. I mean, i think i know that it just has to do with changing the performance of computer to better accomodate the battery but is this an OS task or something that only has to do with the cpu and/or gpu and/or the chipset? Sorry. i do know some things about computers but i'm kind of confused right now. Thanks for being patient.
     
Fusion
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Oct 27, 2005, 02:30 AM
 
No, I don't think that 10.4.3 will improve your battery life. It will be the same for you and it will be the same for the newer powerbooks, the newer ones will have better battery life and the old ones will not. Even if the hardware WAS the same, Apple would probably still keep it that way just for marketing reasons.

And I guess i was misinformed about both the battery and the screens. I could have sworn the model screen they chose this time was more energy efficient. Sorry.
     
brent0saurus  (op)
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Oct 27, 2005, 10:00 AM
 
shoot! I'm getting really sick of this terrible battery life. Oh, well...i just have to accept that technology does get better and I will pay more money for something that will come out months later that is cheaper and better.....sigh.
thanks for all of your answers and feel free to keep more coming!
     
ibook_steve
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Oct 27, 2005, 01:11 PM
 
Originally Posted by Fusion
No, I don't think that 10.4.3 will improve your battery life. It will be the same for you and it will be the same for the newer powerbooks, the newer ones will have better battery life and the old ones will not. Even if the hardware WAS the same, Apple would probably still keep it that way just for marketing reasons.

And I guess i was misinformed about both the battery and the screens. I could have sworn the model screen they chose this time was more energy efficient. Sorry.

Trust me, if Apple could get better battery life on all machines in an OS update, they would. It's ridiculous to say that they wouldn't for "marketing reasons." The new machines have newer processors that can support speed stepping. The older ones could not. That's why we had to play tricks with the bus frequency (DFS) to get power consumption in line. Changing the speed of the processor is a hardware/software interaction that simply isn't possible with the older Powerbooks.

Steve
     
brent0saurus  (op)
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Oct 28, 2005, 12:22 PM
 
siiigh, oh well. Maybe i can get my powerbook replaced with a new one because of a bunch of minor issues i'm having with it. i.e., scrolling trackpad not working on the extreme left and right sides, lagging volume buttons, and things not running as fast as i think they would with 1.5 GB of ram....
well, thank you all for your responses!!
     
amazing
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Oct 28, 2005, 02:35 PM
 
IMO, Apple gets to talk about better battery times because it seems to have implemented draconian power-stepping measures. The user can no longer specify "reduced-automatic-highest" energy saver options. Some preliminary results seem to indicate that the new laptops can be slower than the same-GHz previous generation when operating on battery, because of the draconian power-stepping. The whole shebang is pretty unclear at present, but we can only hope that more research will prove me wrong.

Since the energy saver options are implemented via system software, as soon as the newest system software comes out, we can expect that lack of choice to also be implemented for all laptops. In other words, better battery management is in our future as well, because it will be implemented in system software, willy nilly.
     
amazing
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Oct 28, 2005, 02:38 PM
 
edit: database error
     
John123
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Oct 28, 2005, 03:08 PM
 
Originally Posted by brent0saurus
siiigh, oh well. Maybe i can get my powerbook replaced with a new one because of a bunch of minor issues i'm having with it. i.e., scrolling trackpad not working on the extreme left and right sides, lagging volume buttons, and things not running as fast as i think they would with 1.5 GB of ram....
well, thank you all for your responses!!
I give you about zero chance of this happening. "As fast as I think they would" is hardly justification for anything. Believe me, I had 1.5GB of RAM, and I know what you're talking about, but that's just a downside of Apple PowerBooks and OS X in general.

As for your trackpad, they'll send you a box to ship yours in, and they'll replace the trackpad.

But sorry....no way they'll give you a new one. That's what they have a repair unit within the company for.
MacBook Pro 15" -- 2.2Ghz, 4GB, 200GB 7200rpm
iPod Nano 2G -- 8GB
     
inkhead
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Oct 29, 2005, 01:47 PM
 
What the hell is everyone talking about? I just bought a new 15" powerbook and the performance settings are directly in the menubar. Same as my old 15" and YES they are different resolutions, and different builds of OS X. This isn't something specific to the 17"?
     
   
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