Effect of enlarging a GUI by a factor of 2

Suppose a typical GUI is enlarged by a factor of two (all sizes, distances, images, buttons, etc.) what effect will such a change have on the speed of pointing interaction, assuming the interface worked properly before?

My thoughts:
This seems to be an application of fitts law. And a normal reasoning says that
Since the distance doubled and the size of the target also doubled so the speed
will remain unchanged. I am not sure if that is correct.