Since I have been considering a new iBook G4, I've looked into the same question, and found that transintl.com offers a 1 GB chip for the iBook G4s. It costs $449. I don't know about older iBooks. http://www.transintl.com/macupgrades/index.cfm Hope this helps, Mike W. Gary Archer wrote: >I have not been able to discover if the iBook would support a 1GB SODIMM >add-on or is it physically or firmware limited to a 512M add-on. > >Any ideas from the group? > >Thanks > >Gary > >