[quote="Davioware":3fbbsg2v]Will an object with effects that is larger than the screen waste processing power by rendering the sprite area which is outside the screen?[/quote:3fbbsg2v]
No. Graphics cards are way too optimised to do something as inefficient as process offscreen pixels. The case Rich described will cause only the visible area to be flipped, which could appear incorrect. However, this is a limitation imposed by Construct (the clever coordinate systems graphics cards use can cope with that situation), but I don't see a need to fix it, since you don't need a shader to flip an image.