This may seem a little obvious. I have a white 24 Inch Imac G5 . . .bought it in 2006. It has the 1gb of memory that came with it. I am doing a lot of design stuff, and need to upgrade my memory . . .very soon. it says in my owners manual that I can upgrade to 3gb . . .so I am assuming then that there is one slot available to me. I found a site through a friend, that looks as though it sells reasonably priced memory, so if I was to order some RAM from here: http://www.centrecom.com.au/catalog/default.php?cPath=115_23 Which one do I get?.