The iBook G4/800 had 128MB soldered to the motherboard. The iBook G4/1Ghz had 256MB soldered to the motherboard.
I think this iBook G4/800 LowEndMac.com link is wrong in saying the machine takes PC133 RAM (it takes PC2100) and that it's expandable to 640MB (it's really 1.12GB with a 1GB module, which may not have been available at the time of release so I'm not sure).
Now I'm getting a headache. This isn't as bad as when Apple did that funky Performa model stuff (631CD vs. 635CD
). I'm done pasting links for the night. Goodnight... 
Voch
I think this iBook G4/800 LowEndMac.com link is wrong in saying the machine takes PC133 RAM (it takes PC2100) and that it's expandable to 640MB (it's really 1.12GB with a 1GB module, which may not have been available at the time of release so I'm not sure).
Now I'm getting a headache. This isn't as bad as when Apple did that funky Performa model stuff (631CD vs. 635CD
). I'm done pasting links for the night. Goodnight... Voch