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DVGuy · Feb 9, 2005, 10:08 AM

Is there any disadvantage to using the "Highest" processor setting in the Energy Settings? Is there some reason why Apple doesn't use it as the default for plugged in PowerBooks?

jzdziarski · Feb 9, 2005, 11:05 AM

I would think that it would generate more heat, and ultimately lead to higher risk of overheating and shorter logic board life (especially with the lid closed, if you're using nosleep). Doesn't automatic bump you up to full speed if your processor demands are high enough?

macaddict0001 · Feb 9, 2005, 12:01 PM

there is nothing wrong with it.

cmoney · Feb 9, 2005, 12:07 PM

I've noticed that on my new 12" PowerBook, setting it to "highest" results in the fan turning on high pretty often. That sucker gets pretty hot with "highest" even when I'm not doing that much. On automatic though, the fan barely turns on.

TonTaub · Feb 9, 2005, 12:55 PM

When using Finder and pointing at an multimedia file like a MP3 my PoBo generates a very tiny but noticeable fizzeling noise. A bit like as if an inductor or a coil vibrates at very high frequencies.
That's something inside the box, not from the speakers.

This noise becomes more intense and louder when switching to "highest".

Hence I'm changing modes when I need more power.
And yes, the fans go on more frequently without doing anything. So I'd say it's getting warmer.

HTH, Michael.

Mike656 · Feb 9, 2005, 07:01 PM

Originally posted by TonTaub:
When using Finder and pointing at an multimedia file like a MP3 my PoBo generates a very tiny but noticeable fizzeling noise. A bit like as if an inductor or a coil vibrates at very high frequencies.
That's something inside the box, not from the speakers.

This noise becomes more intense and louder when switching to "highest".

Hence I'm changing modes when I need more power.
And yes, the fans go on more frequently without doing anything. So I'd say it's getting warmer.

HTH, Michael.

I notice the exact same thing on my PowerBook also, especally when transfering at max speed over AirPort.

TailsToo · Feb 9, 2005, 11:29 PM

Does anyone use the Automatic setting? It scares me for some reason...

cmoney · Feb 9, 2005, 11:30 PM

Originally posted by TailsToo:
Does anyone use the Automatic setting? It scares me for some reason...

Why would automatic scare you? That's the default config.

crazeazn · Feb 10, 2005, 06:26 AM

Originally posted by TonTaub:
When using Finder and pointing at an multimedia file like a MP3 my PoBo generates a very tiny but noticeable fizzeling noise. A bit like as if an inductor or a coil vibrates at very high frequencies.
That's something inside the box, not from the speakers.

This noise becomes more intense and louder when switching to "highest".

Hence I'm changing modes when I need more power.
And yes, the fans go on more frequently without doing anything. So I'd say it's getting warmer.

HTH, Michael.

i think i get that noise as well under intense cpu usage. or when the notebook doesnt have adequate ventilation. however i get the noise only when i move the notebook a little if i pick it up to move or gently shake side to side. it sounds a little bit like a light saber. does anyone else experience this? is this normal? maybe i should change my cpu settings just to automatic and leave it alone.

TailsToo · Feb 10, 2005, 11:15 AM

Originally posted by cmoney:
Why would automatic scare you? That's the default config.

Well, from the old, old PowerBook days, I remember the hell that was processor cycling (apparently Apple only considered mouse or keyboard movement as actual use - other than that, the processor would slow down to a crawl.

jzdziarski · Feb 10, 2005, 11:21 AM

I'm not sure why nobody has a problem with this; heat shortens life span on any electronic equipment. The amount of heat generated when on "High" is considerable. "Automatic" CPU frequency scaling is the only setting that makes sense unless you know you're going to be doing some intense crunching over a certain duration of time.

Overheating will slow that sucker down too. I've had numerous problems when I overheat with other laptops - on one, the second memory slot failed to work requiring a complete system board replacement. On the other, I ran my wireless 24x7 with high levels of throughput, and before I knew it I fried my card. The same things can happen if you leave your cpu at max.

These things don't have the same cooling capacity as towers. Do you want your laptop to last a year or 10 years?

SoCal_BigFoot · Feb 10, 2005, 11:51 AM

Originally posted by jzdziarski:
Do you want your laptop to last a year or 10 years?

10 years?! Do you still use your Pb 500 or 5300?
get back to Earth dude, 10 years!

jzdziarski · Feb 11, 2005, 08:51 AM

When the OS becomes obsolete, you can always install Linux and make these things nice little pancake servers 10 years from now.

jpg71 · Feb 11, 2005, 01:36 PM

Originally posted by jzdziarski:
When the OS becomes obsolete, you can always install Linux and make these things nice little pancake servers 10 years from now.

Or just keep OS X on it - what Linux requirement do you have that has no OS X counterpart?

As for keeping it on high settings - I think automatic does a good enough job of scaling the performance settings when applications call for it.

If you're doing something intensive, say playing World of Warcraft, wouldn't the automatic setting kick it up a notch whereby it would be operating equivalent to highest setting anyway?

cmoney · Feb 11, 2005, 04:56 PM

Originally posted by jpg71:
As for keeping it on high settings - I think automatic does a good enough job of scaling the performance settings when applications call for it.

If you're doing something intensive, say playing World of Warcraft, wouldn't the automatic setting kick it up a notch whereby it would be operating equivalent to highest setting anyway?

Take a look at this result. It's a real world example of how much difference the High setting makes vs. Automatic:

http://www.macintouch.com/perfpack/c...son.html#mpeg4

As for running machines for 10 years, I've got 2 laptops at home that are 10 years old (one Compaq, one PowerBook) and neither one is useful at all.

Honestly 3 years is the max life for my laptops. After about 5 years, it becomes extremely hard to find parts like batteries or memory without paying premiums.

jpg71 · Feb 11, 2005, 05:50 PM

Originally posted by cmoney:
[B]Take a look at this result. It's a real world example of how much difference the High setting makes vs. Automatic:

http://www.macintouch.com/perfpack/c...son.html#mpeg4

Interesting results. Sounds to me that when plugged into AC and doing something intensive (playing 3D games, making movies, encoding music, forecasting complex weather models, designing weapons of mass destruction, etc...) it would be a good idea to set it to highest performance.

I guess I'm surprised that 1) it doesn't automatically kick into its highest performance mode when applications start taxing the system, and 2) the PowerBook doesn't automatically switch to highest performance mode when it's plugged into AC.

Will keeping it on high for prolonged periods of time reduce the longevity of the machine? Of course we all know this to be true. But will it happen before or after my Applecare runs out? Since Applecare lasts as long as I keep machines around as primaries, I guess it's a moot point.

Thanks for the benchmark link - good stuff to know.

iREZ · Feb 11, 2005, 06:33 PM

I used to have my PB set so that when I was plugged in I had Highest Performance, but when I ran on battery it was on Longest Battery Life. After a reinstall due to some bizarre font confict (my fault) my PB will not automatically change from HP to LB unless I change it myself. I'm planing on reinstalling my machine again in a week or two (Out of habit and wanting to get rid of any lil thing I don't need on my cramped 40gig drive), hope it fixes this issue cuz I hate running on Auto.

porieux · Feb 12, 2005, 04:16 AM

If using the processor at full speed hurt the laptop that would be pretty lame, that's what it is intended to do. Anyway, that's what AppleCare is for

Ruahrc · Feb 12, 2005, 07:52 AM

I have always used automatic, it has really never bothered me. What I would really like to know, however, is what speed the CPU reduces down to when running on "automatic (low)" or "longest battery life"? I have a 1.33GHz G4. Is there a program out there that tells you this?

Ruahrc

Simon · Feb 12, 2005, 08:16 AM

Originally posted by Ruahrc:
Is there a program out there that tells you this?

I would imagine ioreg could give you this information, but I have no idea what pattern to do a grep on for the CPU speed. You get battery info the same way:

> ioreg -l | grep -i IOBatteryInfo

wilsonng · Feb 12, 2005, 09:49 AM

Does automatic really throttle the CPU higher and lower depending on CPU demand?

I always thought it just changed the time settings for various things like processor performance, sleeping the HD and display, as well as time settings for sleeping the PB.

electric monk · Feb 12, 2005, 05:34 PM

This applies only to the 7447A or better Freescale processors.

Dynamic frequency switching (DFS) conserves power by lowering operating frequency, divide by two and divide by four are included. Also included are voltage and frequency scaling. The chip can be operated at a lower core voltage (and lower core frequency) to reduce power consumption.

Freescale says DFS allows software on the fly adjustments of clock frequency, however they say that only divide by two and divide by four are included. Since it is software it seems possible that a greater range of options could be coded.

jzdziarski · Feb 12, 2005, 07:56 PM

k...so how can you find out what the actual speed your processor is running at is? I would have thought there'd be something in ioreg or sysctl, but all of the values stay the same on ac or battery, whether it's reduced or full.

Ruahrc · Feb 12, 2005, 10:55 PM

So this post has gotten me interested in this whole thing- I did some very basic testing the other day and found that indeed Highest performance is faster than Auto.

The tests were pretty simplistic, and not quantitative at all (well except one) but it seems like putting it on Auto, the PB will not dynamically scale the proc speed as often as it should. For example, I opened up about 50 pictures in GraphicConverter, and then used Expose. When it was on Highest, the animation was noticeably smoother than with Auto. Also, the OS just seemed a little snappier with Highest. The one test where I actually measured something was adding a reply to a post here at MacNN. In the reply window, all those smiley-face GIFs in the lower left make things choppy on Auto. But it improves on High. I held the "l" key down for about 10 seconds, and measured how far it got on Reduced, Auto, and High. High was the longest by about 10%, Auto was next, and Reduced was at about 60% the length of Auto.

The only drawback I see to Highest is the higher heat output and also that "crackling" noise which occurs much more often with Highest than Auto (where it hardly ever happens) What in the world is this noise and why is it there!? Any way to stop/muffle it? Solid state electronics are supposed to be silent

Ruahrc