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Processor Speed (Actual vs Reported)
- Thread starter crazzyeddie
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usually incorrect mhz readings only happen with cpu upgrades, never apple retail chips. be assured though that even if the wrong speed is reported that it is still what ever speed the chip is. my sonnet G4/500 upgraded lists as a G4/500MHz in about this mac under 10.3.1 but in system profiler it lists cpu type as "PowerPC 60?" when it is really a 7410 revision of the G4.
don't know if the mystery about this processor lag has been solved so I'll add my 2¢...
I've heard that this is related to the ability to reduce the cycling speed to conserve power. Must be a bug a that keeps that option on even when its not. I'll add a link if I can find one...
http://docs.info.apple.com/article.html?artnum=14449
I've heard that this is related to the ability to reduce the cycling speed to conserve power. Must be a bug a that keeps that option on even when its not. I'll add a link if I can find one...
http://docs.info.apple.com/article.html?artnum=14449
crazzyeddie said:Just as an update, 10.4 seems to have solved this problem, so no more conspiracy theories
Yeah apple just wrote code for your powerbook to fake you out and show 1ghz instead of its true 667 speed.
Wow, this is interesting to me because I realised my 1.5GHz pbook was switching down speed when I got it a year ago using the same commands everyone here is now talking about.
Every so often I would notice apps running slow even though I was plugged into power and with the cpu to run at highest performance. Often when this happened checking sysctrl hw.cpufrequency would say it was running fast but I just didn't believe it.
Finally, by running SkidMarks in the dev tools I found out the truth... whenever I felt it was slow and I checked in SkidMarks then sure enough that would report running at half-speed even though sysctl hw.cpufrequency said full speed! When this slow down occurs in this manner (still plugged in and cpu set to high but just not working at full speed) there is no way whatsoever to get the cpu back to full speed without restarting. Putting the pbook into sleep and using it again in the morning didn't work... it was still on the slow speed. Trying to ignore it and hope it would somehow jump back up to speed at some point didn't work even though I kept waiting for 3 days without a restart. Unplugging and replugging power didn't work and changing energy prefs had no effect. The only way I could get it to switch back up to full speed was to fully shutdown and leave the pbook alone for about an hour. Then when I restarted it would be back to normal.
Strangely enough, SkidMarks is the only Apple app I trust to accurately report the cpu speed and they mysteriously stopped distributing it in the dev tools about half a year ago for no obvious reason. Perhaps they are trying to stop people finding out their cpus are stepping down when they shouldn't be by making people rely on sysctl hw.cpufrequency which definitely lies about what speed the cpu is currently running at.
Anyway, after all this I did discover what causes the cpu to step down to slow speed and stay there. Whenever I use the pbook on a soft surface like on my blanket in bed or sitting on the sofa it steps down speed and won't step back up until I go through the process I described. Clearly, what's happening is that the machine is overheating and for some strange reason after a while, instead of using the fans to cool down, it decides to just keep the cpu on a slow speed from then on in. Indeed, when it gets in the stuck on slow state the fans never kick back into full. Even if you leave the machine on sleep for a day and it's totally cold then the stubborn thing won't kick the cpu speed back up. Once it's made this decision it just sticks on slow until you shutdown for a while. I easily solved my problem by putting a hardback book under the pbook when using it in bed which keeps it cool enough. But sure enough if I ever remove the book and just put the pbook on the blanket then fifteen minutes later its in "stuck on slow until you shutdown" mode.
Sorry for the massive post but as you can see I looked into this quite a bit. If you learn one thing from this post I would like it to be not to trust hw.cpufrequency under any circumstances. Check with "Skidmarks GT.app" which you can still get by grabbing the OLD (version 3 and maybe 4.0) CHUD tools from...
ftp://ftp.apple.com/developer/Tool_Chest/Testing_-_Debugging/Performance_tools/
Every so often I would notice apps running slow even though I was plugged into power and with the cpu to run at highest performance. Often when this happened checking sysctrl hw.cpufrequency would say it was running fast but I just didn't believe it.
Finally, by running SkidMarks in the dev tools I found out the truth... whenever I felt it was slow and I checked in SkidMarks then sure enough that would report running at half-speed even though sysctl hw.cpufrequency said full speed! When this slow down occurs in this manner (still plugged in and cpu set to high but just not working at full speed) there is no way whatsoever to get the cpu back to full speed without restarting. Putting the pbook into sleep and using it again in the morning didn't work... it was still on the slow speed. Trying to ignore it and hope it would somehow jump back up to speed at some point didn't work even though I kept waiting for 3 days without a restart. Unplugging and replugging power didn't work and changing energy prefs had no effect. The only way I could get it to switch back up to full speed was to fully shutdown and leave the pbook alone for about an hour. Then when I restarted it would be back to normal.
Strangely enough, SkidMarks is the only Apple app I trust to accurately report the cpu speed and they mysteriously stopped distributing it in the dev tools about half a year ago for no obvious reason. Perhaps they are trying to stop people finding out their cpus are stepping down when they shouldn't be by making people rely on sysctl hw.cpufrequency which definitely lies about what speed the cpu is currently running at.
Anyway, after all this I did discover what causes the cpu to step down to slow speed and stay there. Whenever I use the pbook on a soft surface like on my blanket in bed or sitting on the sofa it steps down speed and won't step back up until I go through the process I described. Clearly, what's happening is that the machine is overheating and for some strange reason after a while, instead of using the fans to cool down, it decides to just keep the cpu on a slow speed from then on in. Indeed, when it gets in the stuck on slow state the fans never kick back into full. Even if you leave the machine on sleep for a day and it's totally cold then the stubborn thing won't kick the cpu speed back up. Once it's made this decision it just sticks on slow until you shutdown for a while. I easily solved my problem by putting a hardback book under the pbook when using it in bed which keeps it cool enough. But sure enough if I ever remove the book and just put the pbook on the blanket then fifteen minutes later its in "stuck on slow until you shutdown" mode.
Sorry for the massive post but as you can see I looked into this quite a bit. If you learn one thing from this post I would like it to be not to trust hw.cpufrequency under any circumstances. Check with "Skidmarks GT.app" which you can still get by grabbing the OLD (version 3 and maybe 4.0) CHUD tools from...
ftp://ftp.apple.com/developer/Tool_Chest/Testing_-_Debugging/Performance_tools/