I recently purchased a new iMac. It is a great machine, but I have noticed that when it has been running for an hour or two, it gets extremely hot. I used a thermometer to check the temperature of the case (from the outside). I got on the first test: 102.1F Second: 105.4F Third: 107.2F Fourth: 108.3F. Each test was done ~5min apart. Should I be concerned about this?