Hello, I created an account when I got a used early 2008 iMac. It is a 20" C2D 2.4ghz. You guys helped me upgrade it from 2gb to 4gb of ram. Thank you again for your help. I am running OSX Mavericks as I have seen how many people didn't like Yosemite. These days even if all I have open is a browser, usually FireFox or Chrome, after I open a few pages all of my ram is used up and memory clean needs to run and clean things up. I chose to go to 4gb because that was the official maximum, but I just took a look at the cost of 2 4gb chips and I do not think I want to put more money in an older machine. Does anyone have any advice on how to reduce the ram use?