I've got a 6 Day old i5 which is running at 40c right now which is cooler than my old imac. However the HDD is steadily increasing and is now at 46c. My old drive used to regularly reach 50 but I was wandering what the tolerances are for the HDD and at what temps the fans should go above 1100 rpm for the hdd without smc or anything. p.s. to join the debate about noisy hard drives I have the seagate 1tb which makes rumbles when booting and for a few minutes after but here at 2hrs 30m uptime the machine is totally silent.