I'm looking to buy a 20" iMac. I went to our local Apple retailer (Manila, Philippines) and inquired about the iMac's 1GB RAM. I told them I wanted to buy an additional 2GB RAM so that total RAM would be 3GB. They told me that the iMac's stock 1GB RAM is actually 2 x 512MB RAM sticks instead of 1 x 1GB stick. Is this really the stock RAM set-up??? They also told me that if I upgrade the iMac's RAM, it should be upgraded as a pair -- meaning if I put a 2GB stick in one slot, I should also put another 2GB stick in the other. Is this correct? THanks in advance for your help/inputs. Runner10 PS: Additional Q, which machine is better -- 2.0Ghz w/ 4GB RAM or 2.4Ghz w/ 1GB RAM?