Purchased a new iMac a month ago, and it came with 8GB of RAM which I thought would be fine. It seems like the system is running VERY slow and always seems to be using all available RAM. On Apples website it says that the RAM is not user upgradable but I should take it to an authorized service center. The 2 service centers I contacted says it cannot be done. I am past my 14 days to return this thing, any ideas?