Powerbooks and Variable Timing

MacRumors

macrumors bot
Original poster
Apr 12, 2001
46,727
8,945
PowerPage.org claims that upcoming Powerbook revisions may employ new motherboard technology involving variable timing to extend battery life:

Prototypes have been seen sporting a new "variable timing bus and processor" in which the processor and the bus speed are governed by processing demand, a sort of high/low mode which effectively doubles battery life for such mundane tasks as watching DVDs or listening to music CDs.
This is presumably distinct from the processor cycling advantages that current laptops already perform to increase battery life.

Powerpage continues to maintain a January release of new Powerbooks.
 

OneTraveler

macrumors member
Oct 16, 2002
62
17
End of the Earth
New PowerBooks with Timing

Now this is a great thing! I know that I have seen huge drops in powerusage with my TiBook since swithing to OS X....it would be nice to get that life back.
 

benski

macrumors newbie
Oct 20, 2002
2
0
Pittsburgh, PA
what about audio / midi timing?

What about MIDI and Audio timing? From my experimentations with CoreAudio/CoreMIDI, it seems they use number-of-clock-cycles to determine timing. I wonder how timing would be done on variable bus and cpu speed systems ...
 

MacBandit

macrumors 604
Re: New PowerBooks with Timing

Originally posted by OneTraveler
Now this is a great thing! I know that I have seen huge drops in powerusage with my TiBook since swithing to OS X....it would be nice to get that life back.
Don't you mean huge increases in power usage? Meaning it draws more battery power shotening battery time?

This is different from the current processor cycling because it includes BUS speeds. At least that is what I get from the article.
 

Falleron

macrumors 68000
Nov 22, 2001
1,609
0
UK
Anything to increase the battery life is great. However, I think waiting until January is tooooo long.
 
I'd like that!

I was a really happy cow with the Powerbook G4 (400). But ever since I've moved to the current model with OS X, the battery drain is pretty bad. Is Mac OS X a real bad boy when it comes to battery life? I know it was with previous OS X versions since it didn't have energy saving control. But even with 10.2, I still feel that it's behaving badly.

Well, I guess I can't expect the same battery life between 400 and 800 either...

I may be the real bad boy here, huh?

Anyhow, I would be very much interested in this battery saver technology! But I won't buy the third TiBook just because of the battery life.

WHAT ELSE, I wonder???
 

Telomar

macrumors 6502
Aug 31, 2002
260
36
Unfortunately OS X's propensity for being hyperactive and shuffling data around causes a higher power drain than OS 9 used to. Its one of those things Apple is still working on and it really isn't easy to fix because it basically means redesigning and altering things within the kernel.
 

jettredmont

macrumors 68030
Jul 25, 2002
2,706
303
Re: Powerbooks and Variable Timing

Originally posted by Macrumors
PowerPage.org claims that upcoming Powerbook revisions may employ new motherboard technology involving variable timing to extend battery life:



This is presumably distinct from the processor cycling advantages that current laptops already perform to increase battery life.

Powerpage continues to maintain a January release of new Powerbooks.
Not sure about PowerBooks (I only have a Wintel laptop), but Intel/AMD "mobile" chips have employed "speed step" technology for quite some time. "Speed Step" reduces the operating speed of the CPU (by reducing its clock multiplier, leaving the bus speeds constant) to a fixed low-power setting whenever the BIOS notes that the computer is running on battery power. This happens regardless of CPU activity, and has been known to cause "hiccups" in early implementations of the BIOS (ie, you'd unplug the laptop and it would freeze up for a few seconds or indefinitely, or plugging/unplugging within a certain time interval would cause a BIOS panic and it would shut down).

It's hard to judge from such a brief rumor, but it sounds like the upcoming PB technology is more akin to what Intel is aiming to do with its Banias processor, although the addition of reducing bus speeds is, I think, beyond Intel's current plans. The "variable" nature, if accurate, is also an advantage over Intel, which is "fixed" in speeds (ie, Intel SpeedStep is like a three-way lamp except the "medium" setting doesn't exist: it's either on "high" or it's on "low" or it's "off"; "variable" timings would be more akin to a wall dimmer switch with a relatively "infinite" number of settings between "high" and "low".) This would allow the laptop to more appropriately use power in the middling situations where "low" speed isn't enough processing power for the app, but "high" speed isn't necessary. Banias technology does retain the advantage, however, of being able to purportedly switch off sections of the CPU that are not in use, which would be like taking power from the AltiVec unit when not in use or the FPU, and only restoring it when an instruction that uses that unit shows up in the pipeline.

CPU load-based power cycling is a neat trick, but also relies on the fact that software has to be able to tell the OS and hence the BIOS if it is "really" using all those CPU cycles for a user-dictated reason (ie, rendering a frame of a movie) or if it is just "taking advantage of" free cycles to do its processing and has no user mandate to get its work done quickly (ie, a scheduled disk indexing operation or automatic virus scan, etc). This could be done on first approximation basis according to the app's threading priority, but that's really not quite the same thing.

Imagine working in your favorite word processor: 99% of the time, "low power" mode gives more cycles than your fingers can keep up with, but when you go to write the thing to disk or do a full-text search on your 700-page novel, you'll want all the cycles the CPU can give you. This is something that Intel/AMD technologies can't do right now, and that the rumor would appear to indicate PowerBooks would handle properly.

So, if January is really the date for such tech to be in PowerBooks, the PB camp will have a HUGE advantage over Wintel notebooks (not that PowerBooks were lagging ...)

Also, regarding OS X and power usage: OS X tries to keep all subsystems active and doing "work" at all times. This allows a whole heck of a lot more "eye candy" and behind-the-scenes niceties to occur than would have been possible in OS 9 or below. By "behind the scenes niceties" I mean not only automated tasks, but also things like prioritizing memory and disk space usage and intelligently managing the preemptive multitasker and keeping memory accesses in check, etc. These are not things that can just be "turned off" easily, as the entire system relies upon these things being done and done properly.

And, yes, you will find that most Unixes are not really the best OS's for mobile machines. Unix just provides too many services to thrive on a battery-powered device. On the other hand, you can fashion Unixes which do well in such situations (like the Linux base of Zaurus handhelds), but that means giving up many underlying services and sometimes some of the overall stability for which Unix is famous.

Note that on my Wintel (HP) laptop, Win Me (just a half step up from OS 9 in terms of complexity) would run (doing "nothing") for about two hours, Win XP runs for an hour and a half, and Linux runs for about an hour and fifteen. Granted, neither XP nor Linux are "tuned" highly to get rid of "sometimes needed" services/daemons, but that's how the battery usages pan out.
 

MacBandit

macrumors 604
Re: Re: Powerbooks and Variable Timing

Originally posted by jettredmont


Not sure about PowerBooks (I only have a Wintel laptop), but Intel/AMD "mobile" chips have employed "speed step" technology for quite some time. "Speed Step" reduces the operating speed of the CPU (by reducing its clock multiplier, leaving the bus speeds constant) to a fixed low-power setting whenever the BIOS notes that the computer is running on battery power. This happens regardless of CPU activity, and has been known to cause "hiccups" in early implementations of the BIOS (ie, you'd unplug the laptop and it would freeze up for a few seconds or indefinitely, or plugging/unplugging within a certain time interval would cause a BIOS panic and it would shut down).

rd processor: 99% of the time, "low power" mode gives more cycles than your fingers can keep up with, but when you go to write the thing to disk or do a full-text search on your 700-page novel, you'll want all the cycles the CPU can give you. This is something that Intel/AMD technologies can't do right now, and that the rumor would appear to indicate PowerBooks would handle properly.

So, if January is really the date for such tech to be in PowerBooks, the PB camp will have a HUGE advantage over Wintel notebooks (not that PowerBooks were lagging ...)
Speed stepping is and has been implemented by Apple Powerbooks for a long time now. I'm not sure when it started but I know that they have been using one form or another of it since they Powerbooks were using pre PPC chips. So we're talking over 10 years now.

Also to answer your other question Apples OS and the chips do speed step very well and from what I know it's a very rare case that the end user even knows it's happening.

Speed stepping at the System Bus will be a huge advantage and should be very beneficial to all users.
 

OneTraveler

macrumors member
Oct 16, 2002
62
17
End of the Earth
MacBandit

------------------------------------------------------------------------
Originally posted by OneTraveler
Now this is a great thing! I know that I have seen huge drops in powerusage with my TiBook since swithing to OS X....it would be nice to get that life back.
------------------------------------------------------------------------

"Don't you mean huge increases in power usage? Meaning it draws more battery power shotening battery time?

This is different from the current processor cycling because it includes BUS speeds. At least that is what I get from the article."



Uhhh, That's exactly what I meant....sorry, late night in Alaska. Sorry.
 

NatronB

macrumors regular
Jul 2, 2002
127
0
patience, patience....

Originally posted by Shadowfax
HUMBUG! I NEED ONE IN NOVEMBER!

You will get your new Powerbook in two weeks.... let's say, November 5th.


Call it a hunch.....
 

robguz

macrumors member
Jan 13, 2002
70
0
Well they need something. Once OS9 is gone, there is no way they can still advertise 5 hour battery life. I get 3.5 max in 10.2.1 on a Ti550. About 2 when playing a DVD with brightness set extremely low. When I use it how I'd like to, with brightness set at max (still too dim) and doing whatever I want without worrying about conserving, it lasts 2 hours also.

I imagine it will only get more difficult to maintain battery life with faster CPUs, video, HDs, etc.
 

MacBandit

macrumors 604
Originally posted by robguz
Well they need something. Once OS9 is gone, there is no way they can still advertise 5 hour battery life. I get 3.5 max in 10.2.1 on a Ti550. About 2 when playing a DVD with brightness set extremely low. When I use it how I'd like to, with brightness set at max (still too dim) and doing whatever I want without worrying about conserving, it lasts 2 hours also.

I imagine it will only get more difficult to maintain battery life with faster CPUs, video, HDs, etc.
Don't forget that battery technology is also progressing. The AFA has recently aprooved the new micro-fuel cell technology for use on commercial airlines. This means we will be seeing cell phones, computers, and many other devices with them soon. Micro-fuel cells promise nearly 3-5times the power output for the same size battery also they take basically no recharge time. They will be revolutionary.
 

shadowfax

macrumors 603
Sep 6, 2002
5,849
0
Houston, TX
macbandit: you may want to search the forums for fuel cells. we had an extensive debate on them at some point. they do require a refill, though not a recharge. i am all for it, granted, but don't forget to mention the "downside."
 

Dr. Distortion

macrumors regular
May 2, 2002
159
0
Eindhoven, the Netherlands
All G3 processors can do instruction throttling, where the processor's instruction cache gets slowed down. I think this technology has existed even since the earliest G3s. I'm curious though about variable bus speeds... would all pcmcia cards still be compatible?

-Dr. D.
 

Santiago

macrumors regular
Jun 14, 2002
195
68
Mountain View, California
I have a Titanium 800 Mhz, and if I throttle it down to 667 (which also turns off the L3 cache) and reduce the screen brightness, I can get about 4:30 of typing time on it--enough for cross-country flight.
 

jettredmont

macrumors 68030
Jul 25, 2002
2,706
303
Originally posted by robguz
Well they need something. Once OS9 is gone, there is no way they can still advertise 5 hour battery life. I get 3.5 max in 10.2.1 on a Ti550. About 2 when playing a DVD with brightness set extremely low. When I use it how I'd like to, with brightness set at max (still too dim) and doing whatever I want without worrying about conserving, it lasts 2 hours also.

I imagine it will only get more difficult to maintain battery life with faster CPUs, video, HDs, etc.
Well, HP advertised 4 hours of battery life for the notebook I have, and I've never gotten more than 2 out of it, sitting idle. If I actually do anything with it (just typing, no CD activity), I could get 1:30 out of it in Win ME and about an hour in XP. Start up the CD/DVD and life falls to about the length of a single CD (45-60 minutes max).

So, Apple calling their PB battery supply 5 hours when it's really only 2 in real-world usage isn't too far afield from what the Wintel world is used to now. I'd love to have 2 hours of real-world battery life on my HP POS.
 

MacBandit

macrumors 604
Originally posted by Shadowfax
macbandit: you may want to search the forums for fuel cells. we had an extensive debate on them at some point. they do require a refill, though not a recharge. i am all for it, granted, but don't forget to mention the "downside."

I get a few science magazines and have read quite a bit about the fuel cells. Also I do realize it is a refill and not a recharge but in the interest of simplicity I simply said recharge as to not cause a rush of questions and explanations. They do generate more heat then normal batteries also. This is a downside that I did not mention. I don't consider refilling a downside since it still takes less time then recharging most batteries.