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Display your CPU's true speed
Authored by: ahbe on Dec 04, '03 11:32:17AM

Here's my question than, if it doesn't display the correct speed right now, does that mean its actually running slower than its supposed to? And resetting the PMU (I assume you mean Power Management Unit) should kick it back into gear and run your CPU at full speed again? So supposedly, many of us are running our computers had drastically slower speeds. Or, is sysctl just reading it wrong all the time. I'm very curious to know the answer to this one. In the mean time I'm going to reset my PMU and see if that fixes it.



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Display your CPU's true speed
Authored by: cks3 on Dec 04, '03 11:51:50AM
systcl reports the wrong info. you can see how it does this by typing
sysctl -a
in your Terminal. In the results you will notice that the numbers hw.cpufrequency, hw.cpufrequency_min, and hw.cpufrequency_max will be reported as all the same. I actually wrote a little Applescript called CPUfrequency that used systcl to "diagnose" whether the PMU needed to be reset. Shortly after releasing it to the world, I was lambasted with emails and comments stating that systcl is faulty and therefore my scripts don't really work. If Apple ever fixes sysctl, then the scripts will work and can be found here. If you look through the archives you will find more detailed discussion of why it does not work.

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Display your CPU's true speed
Authored by: britrock on Dec 04, '03 11:52:42AM

Can someone that is seeing this issue run some benchmark that stresses the cpu heavily, and then reset the PMU, and run the same benchmark?

Its returning the proper value for me



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Display your CPU's true speed
Authored by: ahbe on Dec 04, '03 12:09:26PM

Yippeee! Reseting the PMU works for me. Sysctl reads 866666664 now. So I wonder, how long have I been running at only 533Mhz? I'm amazed that this could even happen. I would think that "About this Mac" should always give you the correct CPU speed, and not some arbitrary number. I'm a bit unhappy with Apple on this one. Shame shame.



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Display your CPU's true speed
Authored by: etyrnal on Jan 17, '04 12:53:52PM
is it possible that the 'speed' being reported by the System Profiler is not a MEASURED speed, but rather a speed that is being returned based on a gestalt ID... eg: maybe when the machine runs tha System Profiler, rather than actually measuring the speed, it just rely's on an Identification stored on the logic board... I say this because i do NOT believe that the System Profiler will report anything less than your machine's TOP-RATED speed... if you have a Powerbook that does cpu speed-switching while on-battery, then try this... Plug the machine into ot's Power Adapter and set the machine to MAXIMUM performance in the Energy Setting Pref Pane... (This should be the MAX cpu speed for your machine)... now run Sys. Prof. It reports your machine's Max Speed (the speed your Model was NAMED as) Now take your machine OFF wall-power by removing it from the Power Adapter and set your Energy setting to Low Power (if you have a machine that is capable of doing cpu speed-reduction it will drop to the lower cpu speed)... Then run System Profiler again... I guarantee that your machine STILL reports the HIGHEST speed... Because it is NOT measuring it... it is reporting the speed NAMED in your Powerbook's Model-Name... eg: an 867MHz TiBook is ALWAYS going to say 867MHZ even though it may be running at 667MHz..
http://etyrnal-no-ip.com


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