Noc, to answer your question the new iMac comes with both a DIMM slot and an SO-DIMM slot, im am not certain as to wether the DIMM slot is accessible by just unscrewing the bottom, because thats where the Airport slot and SO-DIMM slot are located. When you buy the new iMac the DIMM slot will be filled and the SO-DIMM will be left free, unless of course you choose to have in excess of 256mb.