hi , i just upgraded to Mountain Lion clean install and my machine is MBP 15" mid 2009 Model Name: MacBook Pro Model Identifier: MacBookPro5,3 Processor Name: Intel Core 2 Duo Processor Speed: 2.66 GHz Number of Processors: 1 Total Number of Cores: 2 L2 Cache: 3 MB Memory: 8 GB Bus Speed: 1.07 GHz Boot ROM Version: MBP53.00AC.B03 SMC Version (system): 1.48f2 everything works well but i have a little trouble. i always use safari for browsing i always opened a lots of new tab normally 20-30 tabs at once. in Lion i have no problems but after i upgrader to ML when i open about 10 tabs on the safari it started to lagg the whole machine started to lagg i have 8GB ram so i dont think thats the issues from the istat menu cpu monitors the top 2 procceses is webproccess and safari the webprocces can get to more than 100% i dont know whats wrong with it surelly my old core 2 duo peryn proccesors are enough to be used for browsing right ? can anyboddy help me here ? thank you.