Hey everyone, So just to state right off the bad; I have done a clean install of Yosemite after experiencing the same problems when upgrading directly from Mavericks. The thing is, Yosemite on my rMBP 2013 (8gb 256gb SSD) feels incredibly sluggish. Switching to mission control is painstakingly laggy and scrolling through PDF files in viewer has become a real hassle. Also, opening and closing tabs in Safari takes a second or two. I dont know what to do about it, I mean I paid good money for this machine and its not even a year old but running this slow on Yosemite. Any suggestions, I'm getting desperate here?