Despite all of this talk of Win32 being "power hungry" and "inefficient", actually Win32 goes out of its way to avoid redrawing (one of the most power-hungry things your computer does) parts of the window that haven't changed.

Ironically metro games, or anything that uses DirectX / OpenGL which draws as much as possible will completely dwarf any normal Win32 apps in terms of power consumption.

And if power consumption was really that big a deal, Microsoft would make you write in C/C++ and ban javascript and .NET, because the overhead of moving objects around and garbage collection is a power-cost to the device (actually this is the reason why IPhones make you use objective-c instead of java)

So please, let's stop with all the "Win32 is power inefficient" FUD.