Comment Re:Easy one... (Score 3, Informative) 558
Because it wasn't designed with power management in mind. Duh. The engineers who wrote some of the subsystems probably took shortcuts that they knew would suck up power (indefinite loops or some such) but were easy to implement. It is a desktop OS.
BSD, on the other hand, was built with embedded systems in mind.
No, it wasn't. If we go back to 3 and 4BSD, it was built with VAXes in mind; even if we only go back to {Free,Net}BSD (Open and DragonFly forked off from them), it was built with PeeCee's in mind.
And NeXTStEP/OS X were also originally designed for desktops.
Desktop Linux, I hear, is pretty rough on power too, but not as bad as Windows.
Linux was also originally built with PeeCee's in mind.
So Windows, OS X, Linux, and *BSD were all originally built with personal computers in mind; all the power-saving stuff largely came later, as 1) notebook computers became more popular, 2) some of those OSes were taken into lower-power embedded systems, and 3) some of those OSes were taken into smaller mobile computers.