Determining true processor speed under Mac OS X 10.2.x
Determining true processor speed under Mac OS X 10.2.x
Attempting to determine the actual speed a processor is running at (rather than the maximum set clock speed) under Mac OS X 10.2.x can be a somewhat difficult task. The speed of the processor is modified by toggling Energy Saver preferences to increase battery time, but Mac OS X (unlike Mac OS 9) displays the manufactured clock speed rather than the actual running speed in the Apple System Profiler.
MacFixIt reader Bob Patterson writes:
"I recently installed 10.2 with the 10.2.4 Combo update onto my iBook 700 (16 MB VRAM) from the Spring 2002 release (Mine arrived from BTO on 7/3/02). All seems to work well, except that now there is no way I can find to determine what speed the CPU is running. The CPU in the iBook can run in either 'Highest' or in 'Reduced' performance in Energy Saver. In OS 9, I find that this is toggles between 700 and 400 MHz. I also believe I recall that Apple System Profiler under 10.1.5 would also report the speed of the CPU.
"But now, both Apple System Profiler and About this Mac, as well as a few third party applications I've tried, all indicate a constant 700 MHz no matter what Energy Saver setting is selected. However, if I run one of the CPU benchmarking utilities, and then take the ratio of the results at the low to the high performance settings in Energy Saver, and multiply by 700, the result is 398 MHz. That is, such benchmarks suggest that the CPU is actually running at 400 MHz even though everything else I can find says 700 MHz."
Aside from benchmark utilities, there are a couple of small applications that claim to display the "true" processor speed at which your system is running.
One is MegaMyth, a straightforward app that shows your system CPU and bus speed, measured in the same manner used by Apple System Profiler, as well as an IOregistry figure that purportedly shows your actual running speed.
UPDATE: Another tool that tells you this info and significantly more is Apple's own IORegistryExplorer, part of the developer's package, found on your hard drive (assuming you installed the developer's tools) at: /Developer/Applications/IORegistryExplorer.app
Launch this, select "IODeviceTree" under "Service Planes" and then navigate to: Root/device-tree/cpus/PowerPC,G4@0/PowerPC,G4@1.
MacFixIt reader Rob Pattay writes:
"I have a dual processor 1 GHz machine so I have two CPY entries. Anyhow, in here is a ton of info on bus speeds, cache info and the like. It reports for me that my clock-frequency is 3b9ac9fd (=999.999997 MHz (all data is in hex)) and my bus-frequency is 07efdc44 (=133.160004 MHz). MegaMyth reports 998.70 MHz and 133.16 MHz respectively so I'm not sure exactly which clock frequency to believe."Feedback on this issue? Drop us a line at late-breakers@macfixit.com.
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