User profile for user: reezekeys
reezekeys Author
User level: Level 1
5 points

yes or no: force processor to run at full speed on new "HR" PB 15" and 17"

I do music for a living, and need as much processing power as I can get to run virtual instruments with low latencies. I recently bought a new 15" G4 "HR" PowerBook and was a little disappointed in it's performance compared to my previous PB, an original TiBook 500.

I did a little asking and searching and was pointed to this thread: http://www.nabble.com/New-PowerBooks%2C-SC-and-CPU...-ick...-t859454.html

[Summarizing] Apparently the latest PBs' processor automatically throttle down to 1/2 or 1/4 speed depending on the load. The option for "highest performance" is gone from the Energy Saver CP. A message in the thread links to an Apple developer doc that details this.

Now, the user manual does say that setting Energy Saver to "Better Performance" will force the processor to remain at high speed. However the developer doc does not state this, and while the originator of the thread referenced above does manage to improve performance for his app ("Supercollider", a "real time audio synthesis programming language"), I believe he says that he cannot match the performance from a previous 1.67 Ghz (non-HR) model.

I was wondering if anyone had the definitive skinny on this.

1.67Ghz PBG4 "HR" Mac OS X (10.4.2)

Posted on Feb 15, 2006 2:30 PM

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16 replies
User profile for user: JustAnotherFool
JustAnotherFool
User level: Level 1
120 points

Feb 15, 2006 6:29 PM in response to reezekeys

The only way is to somehow disable the power saving funtion but then it will be more noisy and warmer etc. etc.

When the load is there and Higher performance is selected then you can maybe get close to maxing out the processor.

Also open activity monitor select CPU once you start to see the blue nice then you are actually putting strain on the cpu.

I doubt if your software can do it NICE it.

While this is open start Itunes press command+t as this will start the visualizer and set it to windowed and NOT full screen.

On the right hand top corner is a OPTIONS button.

OpenGl FPSMAX Frame rate.

let this run and say open 20 programs then maybe the cpu will start to work.

If you want to nice it try Folding at home as it does some clustering type work to help the medicine guy's test genetic strains or something like this.

This might get you to nice or 50% nice.

Bassically the most you have ever thrown at your PPC G4/G5 is merrely like a annoying fly/bug to the proccessor and merely annoying it while it sleeps.

Get it here: http://macupdate.com/info.php/id/8492 and while running this try to do the music thingy you want and say play UT2004 if you have the RAM then you will max it out and get Max speed performance out of it.

I might be wrong but heck it takes a lot to get her HAPPY/NICE .
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User profile for user: reezekeys
reezekeys Author
User level: Level 1
5 points

Feb 15, 2006 8:14 PM in response to JustAnotherFool

Thanks for the replies but maybe I'm being misunderstood.

It's the actual throttling of the processor speed while doing real-time audio work that's the possible deal-breaker for me in using this machine.

In pro audio work, you could easily be moving 40 to 60 channels of audio through the computer. This is not as much a strain on the processor as it is on the disk system. What kills the processor is that you're often processing the audio in real time through many audio plug-ins, some of which consume plenty of cpu juice (reverbs top the list). The kicker is when you're playing a "virtual instrument" in real-time along with this. There is an input audio buffer that must be set to a pretty low number (for me, 128 samples at 44.1K) after which there'll be an audible delay between playing the keyboard and monitoring the sound produced.

From what I've read, "throttling" the cpu's clock while processing audio can result in processor spikes, resulting in either clicks & pops in the audio, or dropouts.

In 2001 I bought my TiBook 500 hoping to be able to use it in live performance, using several virtual instruments active simultaneously. I found out after a few hours that I wouldn't be able to do this. I'm going to be very disappointed if the same scenario repeats itself with my brand new 1.67Ghz PowerBook. I'm not going to jump to any conclusions yet but I thought by posting here I would at least find out whether this processor throttling is truly non-defeatable.

1.67Ghz PBG4 "HR" Mac OS X (10.4.2)
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User profile for user: reezekeys
reezekeys Author
User level: Level 1
5 points

Feb 16, 2006 6:21 AM in response to SuperSizeIt

Avoid the 1.6 High Res. G4. As far as I can dig up, it not possible to have user adjust capabilities with these CPU.<<</div>


Here's the quote from the User's Guide on page 55:

"To set your computer to use its highest processing speed at all times, choose Better Performance."

I need to know whether Apple is being honest here.

1.67Ghz PBG4 "HR" Mac OS X (10.4.2)
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User profile for user: PieterVD
PieterVD
User level: Level 1
0 points

Feb 16, 2006 6:59 AM in response to reezekeys

i also got the latest 15" powerbook, and i'm disappointed too. i use protools and expected a better performance. it works... but it's not great at all. he can't handle more than 2, 3 virtual instruments.

from what i understand, the previous powerbooks have a better performance? unfortunately i can't switch computer everyday.

i also wasted a lot of time on discussion boards etc... btw i found this on digidesign message board:

"Disabling "CPU Napping" results in the CPU consuming a fairly constant current instead of switching between high and low power usage, which we have seen can cause the noise as you have described, in particularity as Pro Tools is a CPU intense application.

You can also ensure that the Processor Performance is set to the "Highest" setting and that Sleep Mode, Energy Saver, Screen Savers, Software Updates etc... have all been disabled"

I'm not an expert, but could disabling CPU napping improve CPU performance? the initial digidesign thread was about getting rid of the noises in the powerbook. not about improving performance.


Powerbook 15" 1.67 ghz Mac OS X (10.4.4)
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User profile for user: JDee
JDee
User level: Level 5
6,491 points

Feb 16, 2006 7:27 AM in response to reezekeys

Hi reezekeys --

I understand completely what your saying, but unfortunately I can't confirm whether the statement in the manual for the Ocotber '05 PB is accurate either.

I went to the Apple Developer site and presumably found the same information you did regarding the Hi Res PB, but just in case you haven't seen this, here's what the Developer Notes say about Processor Power Management for the 15-inch October '05 PB:

Processor Power Management
To lower power consumption and heat generation, the 15-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 1.28 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 15-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 15-inch PowerBook G4 meets all applicable safety standards, including UL 60950 and IEC 60950.

*********

Compare that to what the Developer Notes say about Processor Power Management for the 15-inch February '05 model PB:

Processor Power Management
To lower power consumption and heat generation, the 15-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. Depending on the configuration, the processor speed will switch between 1500 MHz and 750 MHz or 1670 MHz and 835 MHz. The memory bus speed is not shifted.
Switching between different processor speeds and voltages is achieved by a transition that operates seamlessly to the user and should not impact system or application performance.
The 15-inch PowerBook G4 allows the user to control DFS mode. The options for specifying either high, reduced, or automatic processor and bus 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, for processor performance.
If the 15-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 reduce the speed regardless of the selected setting.
The 15-inch PowerBook G4 meets all applicable safety standards, including UL 60950 and IEC 60950.

And page 55 of the manual for the February '05 revision PB appears to have the same line its manual as does the October '05 PB:

(To set your computer to use its highest processing speed at all times,
choose Highest from the Processor Performance pop-up menu.)

*************

That's the best information I can find so far.

I don't know what applications you're using, but if you don't get the answers you need here, you might try posting in one or more of the Pro Digital Discussion Forums listed on the right side, middle of the Discussion Home Page, here: http://discussions.apple.com/index.jspa?categoryID=1 perhaps users there might be able to advise as to whether specific applications work well with the October '05 revision PB.

Good luck.

-- JDee
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User profile for user: SuperSizeIt
SuperSizeIt
User level: Level 3
579 points

Feb 16, 2006 7:27 AM in response to reezekeys

The guide is wrong. Can't be done on these High Res Powerbooks.

"The DL Powerbooks support both divide-by-two mode, AND, for the first time, divide-by-four mode. That is, the processor will set itself to 1.67GHz, 833MHz and 417MHz as needed for the particular task at hand. There is no user control over this switching; it is automated. Previous Powerbooks with 7447 processors have simply supported divide-by-two, e.g. 1.5GHz or 750MHz, with the user having the option to choose 'highest', 'automatic', or 'reduced'. The source for this information is the developer notes on the Apple Developer Connection website."
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User profile for user: Philip Tyler
Philip Tyler
User level: Level 4
2,261 points

Feb 16, 2006 7:27 AM in response to reezekeys

I would imagine that when the processor detects it needs to run faster it runs faster. So when using your applications as they require more processor power then that is what they get.
I have an AMD Athlon inside a PC using its cool and quiet driver and it ramps the speeds up and down no problem.
My current PowerBook is usually set to Normal in the power settings where it adjusts the CPU as and when needed and it certainly copes perfectly well with iDVD when I use it and that is a real resource hogger! Forget audio or music applications if it can cope with iDVD it can cope with anything. I also use iMovie a lot and do not notice any problems there either. Plus my Nikon slide scanning software is very demanding but I suffer no problems leaving the system to adjust CPU speed.
Phil
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User profile for user: reezekeys
reezekeys Author
User level: Level 1
5 points

Feb 16, 2006 8:08 AM in response to reezekeys

Well it seems like my fears were justified. Thanks everyone for your replies and very helpful info--especially JDee and Pieter. JDee, I did see the info on the HR PBooks but not on the previous rev--it seems very obvious that the CPU speed management is different in the HRs.

The problem is that I haven't yet purchased the software I want to run! So I can't really know for sure whether this new PB will do the job for me or not. I'm pretty bummed that a brand-new computer I planned to get a few years of use from might be unusable right out of the box, before I even have the sw I need!

(JDee, thanks for the tip about posting on the Pro Digital forum, but I'm not a Logic user, so I don't think that's going to help me).

Philip, I understand what you're saying but there is a fundamental difference with audio software. Is iDVD able to let you watch your movie play as it renders it to a finished file? Music software is mostly REAL-TIME. Especially when using virtual instruments in live performance. That's what I need a PB for! (For studio work, I hope to get an Intel Mac Desktop in a year or so).

1.67Ghz PBG4 "HR" Mac OS X (10.4.2)
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yes or no: force processor to run at full speed on new "HR" PB 15" and 17"

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