Im currently running MAC OS Yosemite 10.10.1 on my MBA 13" 1.86ghz 2009 2GB RAM. its laggy at times and the fans is noisy and my mac is heating up. do you think this is MAC OS is just too much for my mac? my daily routine in my mac are: -browsing the web, safari, 2-4 tabs with use of flash -utorrent -microsft word -skype -check speed using activity monitor my RAM use is at 1.80 to 1.99 although my memory pressure is at green level. hope you can advise my the better and latest OS for my MBA. My MBA came with MAC OS Lion but i wanted a higher OS. thank you very much, hope to hear from you guys soon. by the way, im a newbie at this.