I am trying to decide between the 13" and the 15" models and was wondering what tasks would kick in the dGPU for the 15". I plan on using it for light gaming (SC2), photo editing through photoshop/aperture, some light iMovie work and app development along with all the other day to day usage. I will also be installing windows as some of the tool i use are only available on it (design engineering schematic capture and pwb layout). Can the 4000 on the 13" handle all these without any issues? Thanks for your feedback!!