My parents still have an old early 2008 iMac and I'm going to upgrade the RAM in it for them. It still uses the original 1GB of RAM. Looking on OWC it says that the model supports up to 6gb while Crucial says it only supports up to 4gb. The cost difference between the two is about an extra $70 to go from 4gb to 6gb. So my two questions are if that model (8,1) does support up to 6gb and secondly if they're likely to see any difference between 4gb and 6gb for this level of model? I think they still have Snow Leopard installed which I'll probably upgrade to whatever the latest OS that the model supports. Thanks.