Are you running 7.0.0 or 7.0.1?
Were the 4-5 second times using the same resolution images?
Were the 4-5 second times using the same extraction settings?
Try it without the clear area outside screen checked. How much faster is that? The clear feature uses select subject. Version 7.0.1 is suppose to force it to use device mode. However, I wonder if it is using select subject cloud mode which runs much slower.