Hi all! I bought a new iMac 6-8 months ago (21.5", 16GB RAM, 1TB harddrive, 2.9GHz intel core i5 processor) and it has never performed well. All day long I get spinning beach balls, and starting it up means I cannot use any applications for around 5-6 minutes. Constant beach balls doing anything from changing a song in iTunes to switching between programs. After about 10 or so minutes, it gets more responsive. As a comparison, I also have a 13" retina macbookpro I bought about a year ago (8GB of RAM, 256GB harddrive, 2.7GHz intel core i5), and that is running lightning fast. I have colleagues with similar iMac setups, and similar issues, so I doubt it is a lemon. What gives? Upgrading to El Capitan has not helped.