Many websites reported that the built-in memory of Clamshell iBooks (32MB or 64 MB) can only be expanded to a maximum of 288 MB or 320 MB if you use a SO-DIMM module with 256MB. The good news is that several 512MB Modules will work with the iBook.
You should check the following things before the installation of a new RAM module:
1. Firmware upgrade installed? Firmwareupgrade 4.17f is necessary for 256MB and 512MB modules. In your System Profiler you will find you current firmware version. This upgrade needs to be installed under OS9.
2. Compatibility ? Ask your vendor if it works in a G3 iBook. Practical experience shows that most of the 512MB RAM SO-DIMMs that have 8 Chips will work.
3. Reset. The iBook manual recommends that after the installation of a new memory expansion to press the small reset button (right above the Power button) with a paper clip, wait a few seconds and then press the Power button.