I've had couple old MacBook pros, both old style with DVD drive, and those retinas. and one common thing among them is that the fan will never stop. doesn't matter how cool your computer is running, the fan will be running at a minimum speed ~1200rpm. however I notice on the new MBPs, at least 13 inch, when browsing web, the CPU is running @ ~95F, or 35C. that's even lower than human body temperature. and both fans are running at 0 rpm. yes, 0 rpm. so right now the MBP is running fanlessly, absolutely silent just like the 12 inch MacBook. what a bonus.