Hello! Yesterday I put 8 more gb of RAM in my 2010 iMac 21.5, I also updated the system to the latest Lion version. Now I am having huge problem with it, the computer is completely freezing after like 20 minutes of regular usage. On top of that the computer makes a loud beep that is looping while it is freezed! I don't know if it is the RAM or the Lion update that is the problem, but the computer worked perfectly before yesterday... I am going to call Apple on monday if the problem continues, but I want to hear what you guys think as well.