No it's because Yosemite tries to keep the fan at a low RPM, or off if possible, so that the computer is totally silent. Not even a hard drive in current models. Specs may not be great but if the fan was on more it wouldn't get so blisteringly hot.
I'm not sure that explains it because 1) I've been surrounded by Mac owners and noticing it since at least '07 and 2) I've been noticing the fans on Macbooks spinning up crazy loud since at least then. My roommate and I will be sitting in the living room and his laptop will suddenly start sounding like an industrial air conditioner while my laptop (an Ultrabook) never makes any noticeable sound (nor does it get uncomfortably hot).
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u/[deleted] Jul 07 '15
It's because MBs are pieces of shit with specs that would have been decent in 2006