Just last night ordered one of the new 21.5" iMacs, which comes with 4 GB RAM standard (2 x 2GB). I know the iMac has 4 slots so am planning on upgrading the RAM once the computer arrives. My question is, is there any reason (other than the extra cost) why I wouldn't want to add (2 x 4GB) more, giving me 12 GB, rather than adding (2 x 2 GB), for a total of 8 GB? In other words, is there any "advantage" to having: 2 GB 2 GB 2 GB 2 GB Over having 2 GB 2 GB 4 GB 4 GB ??? Does my question even make sense? I guess it's a way of saying, if "paired" memory is good, is "quadded" (not a real word) memory better? Or as long as it comes in pairs, will more always be better than less?