After doing some searching on the Apple Developer site (thinking CHUD had a bug), I realized what was going on. It appears that Apple disables the L3 cache as part of its Energy Saving process on PowerBooks (perhaps iBooks as well). The problem is that the default install on my computer (I assume, having never messed with these settings) was for reduced processor performance both when running on the battery and when plugged in. Battery life is cut one-third when the L3 cache is enabled, so perhaps it makes sense not to have it enabled when running from a battery -- but when you're plugged in, too? The fix:
- Go to System Preferences -> Energy Saver
- Click on "Show Details"
- Select settings for "Power Adapter" from the the select menu
- Click on the "Options" tab
- Make sure the "Processor Performace" select menu has "Highest" selected
[Editor's note: If someone wants to send me a 1ghz PowerBook, I'll gladly test this one myself!]

