i have ibook g4 with 1 slot for pc2100 DDR266 but I want to buy PB 15.2 this x-mas. so i want to get the rams in advance. They are both SO-DIMM 200pin. so can I use the PB's ram in my iBooks g4? do they have the same shape? is it like PC, u have a DDR266 Mainboard and buy DDR400 for the future?