I am considering buying a 13" MacBook Pro Retina for my sister who will primarily be using it for everyday tasks but as she gets older she will be doing more and more photoshop work, I can't see her using it full time for Photoshop but none the less it is a consideration. Considering that the options really lie between a 13" model - intel iris graphics or a 15" model with dedicated or intel iris pro graphics at a far higher cost I am quite torn between the two models. When I spoke to Apple they said that she would definitely need the dedicated graphics card in the 15" model, which seems silly. Will someone with some experience of using Photoshop / iPhoto / Graphics programs on 13" retina, intel iris graphics please tell me their experience, if it's slow etc how slow? Manageable or is it quite useable? She won't be doing any gaming of any description, she will be watching films, though of course I'd expect any mac to be up to that. I would expect imovie to be the upper limit of any video editing works. Hugely grateful for any feedback I get from this given the cost implications and utility hopefully created by choosing the correct model.