A Fantastic Tip I Had Never Heard Of !!!

[Makosuke]

Ok, I just did a very simple test to make sure I'm not totally full of it. This is on a DP G5 2.0 first gen (the one with the really fast bus) with 2.5GB RAM.

Exporting a 19 sec movie clip from iMovie to Quicktime (MP4, high broadband preset quality):

Highest: 107 seconds
Automatic: 108 sec (~1% slower)
Reduced: 157 sec (~47% slower)


Converting a 3 minute MP3 to AAC 160k, highest quality:

Highest: 9.1 sec
Automatic: 9.2 sec (~1% slower)
Reduced: 13.5 sec (~48% slower)


Which is to say that at least in these specific, extended "number crunching" operations there's little if any measureable difference (though I did notice that the fans were a tad louder in the iMovie export on the Highest setting).

It'd make sense that the bigest difference would be on the transition between "idle" mode and "number crunching" mode, so it stands to reason that while in these cases it doesn't make a difference it might in other cases, particularly ones that have a lot of short bursts of calculation. Certainly, it could contribute to the "feel" of slowness if you do a lot of short, intense operations.

Just a little numeric input to this tip to remind folks that Highest isn't going to automatically make your computer feel brand new again, and itsn't always worth the small noise increase.

 

[Arnaud]

Hi everyone,

Explanations about this setting appeared in previous threads, but it's always good to mention it back, as it seems not everyone is aware of it.

The setting is oriented mostly to the G5's and the Powerbook, not available to iBook, eMac or Mini. (I'm not sure about the iMac G4).

I've used it for the last 6 months, and it does clearly improve the reactivity of your machine, especially in small tasks, like use of the Finder etc... As shown in the last statistics, it doesn't really improve the behaviour of the machine in CPU-intensive works of specific programs.
I guess "automatic" means that the CPU is used as its "highest" when working with CPU for long time, and "reduced" when idle; keeping it at "highest" eliminates the transition time needed by the computer to think "hey, it needs CPU power, let's wake it up".

Side-effect is warmth of the machine and noise due to the fans/vibrations, as was heavily supported in a previous thread, especially for iMac G5's (like mine).

Anyway, my machine is in our "study room", and I chose the slightly-louder-but-snappier-machine, always "highest" and happy about it
(And you can still go back to "reduced" when you want to sleep, maybe even automatize the transition from one to the other...)

 

[aznsal612]

yea we had our group of G5 iMacs several months before we learned of this feature, and we do heavy PS and ID work. I can honestly say we gained at least a 40% performance increase. It was like getting new machines.
Why the hell did Apple enable this feature by default on a desktop. Laptops, it's a no-brainer, everybody wants a longer lasting battery. But in a desktop environment what are you saveing? 1.2db?

The fans on the iMac spin constantly and actually heat up quite a bit when put on highest mode. As said by a genius technician.

 

[Arnaud]

yea we had our group of G5 iMacs several months before we learned of this feature, and we do heavy PS and ID work. I can honestly say we gained at least a 40% performance increase. It was like getting new machines.
Why the hell did Apple enable this feature by default on a desktop. Laptops, it's a no-brainer, everybody wants a longer lasting battery. But in a desktop environment what are you saveing? 1.2db?

The fans on the iMac spin constantly and actually heat up quite a bit when put on highest mode. As said by a genius technician.

Oh yeah, I didn't clarify the "noise level"... The added noise (fans) is clearly audible, so much so that I had a hard time after 1 month of owning the machine - a little different from "just 1.2dB more" -. I was feeling cheated, because I really expected a quiet machine, as quiet as the PBs I used to own. I don't mind a slighty noisy unit, as long as it stays under the desk, but not a noisy machine on the desk !

I sometimes get up very early, like 5am, to write down things in the quietest moments and before work. I can tell you, when your house is silent and so is the street outside, the iMac is really loud, too much to enjoy a quiet concentration (but I'm taking extremes here )

A factory-set iMac G5 with "highest" setting would ruin the image of a "whisper-quiet" machine, because it is clearly not, and it might go against the marketing strategy of Apple. (Call that a dishonest move - it's kinda quiet when you choose to lessen its performances...).

Anyway, as posted above, I chose the snappier machine, and found some solutions (to the dismay of my wife):
- be sure the top platform of your computer desk is not made of hollow wood, which amplifies the vibration,
- isolate the foot of the computer from the desk - some people advised a thick phonebook, but it's ugly and unstable, additionally I suspect it becomes stiff with time; I built up a small additional platform, with 6 rubber feet, total of 5cm higher; BE CAREFUL WITH THE STABILITY,
- I checked the reverberation of noise on close walls; I used to have my computer in a corner, all walls would bring back the noise; I moved it aside, and padded the reverberating walls with sound-proof material (this black one with peaks) - well, this is the reason to my wife's dismay... But she surrendered, these 2-3 m2 in the house are for my use, she can always tell her friends "you know, he's a man, he doesn't know about home decoration"...

A!

(PS: additionally, the noise might go down in the winter, for colder rooms ? My, we've got weather-dependant machines now...)

 

[Tahko]

That works with iBook as well! Garageband is quite faster when "better performance" is turned on. I noticed that when I took my laptop to my drummer friend so he could make me some heavy drumloop to use. I wondered why it felt kinda sluggish, then I checked battery saving options and noticed that max power saving settings reduce clockspeed..