Hello. I am a bit confused. How come the 2.5 GHz 21.5-inch model can hold up to 8 GB RAM while the 2.7GHz 21.5-inch model can hold up to 16GB? Do they have different motherboards/number of memory slots? http://store.apple.com/us/browse/home/shop_mac/family/imac/select Is there a noticeable difference the 2.7GHz Quad-Core i5 and the 2.8GHz Quad-Core i7? From the Front page, benchmark from Ivy Bridget iMac has been out. Do you expect that it will be available for purchase this month? I read that there is a heat problem if the Ivy Bridge CPU is over-clocked. We know there is a turbo boost technology that automatically ticks in when demanding applications are being run. If this cause heat problem for the Ivy Bridge iMac? Thanks.