Playstation Move Doesn't Have Much Of An Affect On The PS3's Performance.

The tiny amount of processing was announced as part of Sony's tech presentation of the hardware during GDC. Sony also announced that the hardware takes "less than a frame" to translate motion controls into the gaming experience. In short: you can make really, really good looking Playstation Move games with motion controls as responsive as a standard controller.

[Cheers Joystiq]