So, apparently I missed this, and I was more or less oblivious to it over the past couple of weeks until a friend filled me in tonight, but since the 10.2.8 upgrade, my laptop’s been running at 2/3 speed. And I thought it was just me. How do you tell for yourself? In the terminal, type:
sysctl hw.cpufrequency
If this isn’t the right clockspeed (mine was running at 533 when it should have been at 866), curse Apple, and then shutdown. Once shut down, hold the CTRL-SHIFT-OPTION keys and the power button for 5 seconds to reset the PMU. Boot up and check the frequency again. If successful, it’ll be back up to full speed. Then upgrade to Panther before it resets the speed again. Be sure not to get drives wiped while upgrading.
(Resetting you PMU will also reset your clock, so be sure to network time-sync afterwards)
Also, resetting your PMU is different for different models, here’s the Apple KB article on it: PowerBook and iBook: Resetting Power Management Unit (PMU)