So as we all know, seagate is crap. I had one, was noisy, got it replaced and now i have a completely silent imac (another seagate though). I still don't like seagate, and i honestly think they make crappy products. Anyway seagate knows theres a problem, and their working on a fix. http://www.engadget.com/2011/02/20/momentus-xt-hybrid-drive-causing-headaches-seagate-working-to-f/ That article explains it all, but this could offer a fix for the noisy hard drives "particularly when installed in a Mac. Seagate forumgoers speculate these are symptoms of the XT's magnetic platters spinning down inappropriately, due to an overzealous power management scheme."