All right, this might be a silly question. I just bought myself a new i5 2.5" iMac, and I swapped out the two 2GB RAM modules for a pair of 4GB chips. The 2GB are currently sitting in my desk drawer. But since the iMac has four slots, could I just pop those two in as well for a total of 12GB? I seem to remember pairing being a big issue once upon a time, but I'm not sure that's still the case. Are there issues with this? Should I just wait a little bit until I can buy two more 4GB DIMMs? Or can I just slide those two old ones into the bottom slots and call it a day? Thanks folks.