Greetings... General question. My Older Graphite is working fine. I filled each slot with a 128 card. Is running on Os X.2.8 No problems. Can I pull the two 128 cards and then 1. put in a bigger single memory card (say a 256) in one of the slots? (If so, does Apple sell them?) 2. Can I then install an Airport card in the other slot? (I think I need an adapter). Want to get a few more miles out of this machine. It just keeps working.