Thermal Throttling in Aluminium G4 PowerBooks?

[dan.dem]

After several attempts my 15" PowerBook (2004, 1.3 GHz, 2 x 512 MB RAM, else completely standard) achieved a Geekbench2-score of 800, well above the 685 listed in Everymac.com. I guess Everymac is publishing averages, so a peak score quite above is nothing extraordinary.

After I did some web-browsing with TenFourFox – modern sites with animated ads – hence the fan kicked in – I ran Geekbench2 again and now I barely reached a score of 500.

Does this mean that thermal throttling is also available in PPCs? It had been my understanding this was introduced with the Intels.

I don't think that I have overlooked other factors like background processes or RAM-shortage due to memory leaks in programs I had opened and close before.

Had anybody had similar observations? Do you know about throttling in G4s?

 

[Byrd]

An overheating PowerBook G4 does down clock the CPU, but not as intelligently as current laptop CPUs today.

I found it rare for the fan to fire up on any PowerBook G4 I owned, if yours kicks in relatively soon it suggests the fan is blocked (dust), and thermal paste dried out and in need of replacement.  Cracking open the 15" PowerBook isn't the greatest fun, so I'd try blasting the fan with compressed air first.

 

[dan.dem]

Thanks, @Byrd , I wasn't aware of the down clocking in G4s.

Sub-optimal cooling of my PB? This may well be the case. It didn't receive any hardware treatment at all since new except adding RAM.

I had been clearing out dust of several laptops but was never sure I did it right. All survived but I never felt comfortable spinning the fan with a blast of air, inducing current to the fan's circuit.

Is there a documented way how to do it right? How are you doing it? Are you also blowing from the exhaust side into the 'Book?

 

[AndiS]

I used a 2005 1.5 Ghz 12" Powerbook for many years, first with OS X (10.4 and 10.5) and then with Linux.

It always got uncomfortably hot when used for things like video compression. I still remember the quite common jokes about not using it on your lap if you still planned to have children ;-) I don't think that it throttled down due to hot temperatures tough, only the fan got very noisy. Before I had set up fan control correctly under Linux, I also reached a hard shutoff point (maybe at 85° C) where the PowerBook just turned off instantly. So maybe OS X did throttle down as a means of last resort, but I never experienced a noticeable slowdown while it was running hot. That might be different nowadays, with dried out thermal paste and dusty fans etc...

When idling the PowerBook was well able to throttle down to about half the clockrate, I don't remember the exact values, but I think the steps were 750 1000 1250 and 1500 Mhz.

 

[Byrd]

I had been clearing out dust of several laptops but was never sure I did it right. All survived but I never felt comfortable spinning the fan with a blast of air, inducing current to the fan's circuit.

Is there a documented way how to do it right? How are you doing it? Are you also blowing from the exhaust side into the 'Book?

I've used a standard garage air compressor to blast crud and dust out of hundreds of computers owned over the years.  I usually then follow up with a light squirt of lubricant into the impeller of the fan.  Never had an issue.

 

[dan.dem]

Hmm. Seems I cannot reproduce the alleged throttling of my PowerBook G4. Today it ran for minutes in saturation (media-rich websites @ 100% processor, so kicking in fans aren't necessarily a sign for bad cooling). Immediately after that Geekbench2 results remained around 800.

I observed the presumed throttling with another software setup, having lots of music production/midi-software and Adobe Creative Suite installed. Maybe some of it didn't behave and left processes in the background.

@AndiS: NOT-AUSSCHALTEN (emergency shut down) occurred to me only when my 1st gen MacBook's fan died. In Intel-Macs it's triggered by temperatures above 100-something centi-grades.

BTW: I would like to learn more about your Linux experiences on PowerBooks. Around 2010 I installed Xubuntu and Mint-PPC on a bondy iMac. Stable but performance was lot worse than with MacOS Panther. I skipped installing it on my iBook since I heard about issues with power management and sleep.

@Byrd: So, spinning fans passively with compressed air doesn't seem to do harm. I also use a 5 mm soft paint brush (intended for water colours). Anyway, I'll spend Xmas-holidays with some Arctic Silver treating the three oldest/most used laptops. I had promised it to my girlfriend's daughter, an avid gamer.

 

[AndiS]

When the OS X support for PowerMacs was waning, I switched to Debian Linux and used said PowerBook as my main machine up to about 2009 - So my experiences are a bit dated. I'm a Debian guy and that's what I used. Power and temperature management were working fine, but only after I discovered that installing any of the available power managment tools made it worse (and lead to the hard poweroff due to overheating)

That means - Around 2007 the Linux Kernel and the PowerBook hardware took care of everything just fine. Any other tools that tried to provide more control made the situation worse.

Regardig sleep - I'm not sure but it might be the case that I had to use "Suspend to disk" instead of "Suspend to RAM" when I was running the PowerBook with Debian. It's just too long ago to remember exactly ;-)

I also ran a G4 Mac mini as a Linux server until about 2013. I still have both machines but since they are not useful for productivity anymore, they are back on 10.5 again.

 

[dan.dem]

Thank you @AndiS for your Linux remarks, very interesting. I'll try to be short, obeying netiquette and not writing too much off topic.
Just one thought: I'm annoyed by boastful claims of several Linux-distros how much faster/better they are, when they are just different GUI-flavors over the same (very decent) Debian.

Postscript: AndiS, we seem to dwell in about the same corner of Europe.