I know this sounds like it might be a stupid question, so forgive me in advance if it is. I upgraded my 2011 Mac Mini from Mavericks to Yosemite. I also have the iStats module which gives all kind of useful info. I've noticed since the upgrade that the DC In setting has gotten much lower then it used to. Now it shows a DC In reading of 11.9v with my fan set at 3000rpm and my CPU at ~10% usage. Previously the voltage would be much higher with similar fan and CPU settings. What gives? Was iStats incorrect before and correct now or the reverse. Is Yosemite somehow that much more energy efficient? Any thoughts or am I just being silly.