Correct. However in this case it's the SMC managing it. PMU comes from the PPC era, like CUDA in the clone and 68K times. SMC handles all low level monitoring,

Correct. However in this case it's the SMC managing it. PMU comes from the PPC era, like CUDA in the clone and 68K times. SMC handles all low level monitoring, because it's OS independent reading data via SMART is just a non option. SMC also takes care of how hardware components are initialised and a slew of other things. See > http://support.apple.com/kb/ht3964 http://support.apple.com/kb/ht3964 Secondly, while you can override certain SMC values like fan speeds you can never override the lowest safe values that are hard coded in. In that same vein if the SMC thinks your fan should run faster when you don't want them to, they will regardless.