Hello This is my first post. I was interested in getting more RAM for my iMac. I went to the apple store and to upgrade to 3g it would have worked out to $650. Without having done any price shopping I almost purchased the RAM from apple. I looked on line and found out what the prices should be. I went to the local authorized apple reseller and got my 3g of RAM for $115. The specs state that this iMac will only use a max of 3g of RAM. The salesman told me that he has friends that have put 2X2g chips in the same iMac and the computer regonizes the 4g. Has anybody done this? Oh the memory I purchased was a Crucial 1g and a Buffalo 2g. They seem to be working great. I still get the annoying rainbow circle though. Thanks!