Some performance increases have nothing to do with strain on hardware, or amount of processing. Sometimes, things are designed to take longer than they should, though only maybe 1/2 a second, but the end result to the user is a faster machine. This is one of those tweaks. Minimizing and maximizing does an animation. Watch closely. Pretty quick eh? Still, it does slow you down, and, really, what does it add to your experience? I am all about vanity and aesthetics, but this feature has got to go.
Relish in the fact you will be increasing your productivity by 0.2 seconds per minimize/maximize.
* Open your start menu, go to run, and type in 'systempropertiesperformance'
* From the Visual Effects tab, uncheck 'Animate windows when minimizing and maximizing'
* While you are here, might as well check out the other goodies you can disable.