I know my machine, a 2.8GHz Core 2 Extreme 24 inch iMac with 4GB (Mid-2007 model), is listed as the minimum requirement for compatibility with Mountain Lion, but I was wondering if anyone whose installed Mountain Lion on a similar machine as mine, or lesser, has had any issues with the new OS X "bugging out" or lagging. Is it a smooth experience? I am currently on SL. UPDATE: Downloaded Mountain Lion. All I can say is wow, this update put some new life into my 5 year old iMac, and its blisteringly fast. Solid update from Apple.