my parents have a 1.83ghz core 2 duo iMac (the education one with GMA950 graphics card) and it came with 2x256mb ram. What's better - 2x256 or 1x256 and 1x1GB (because I have a spare 1GB). and the ram that a 1.83 core duo macbook takes is the same ram that the core 2 duo 1.83ghz iMac takes, correct? the imac is running leopard now too. I upgraded them a couple weeks ago from tiger.