I'll try and keep this simple. I need a new rMBP as my 2012 isn't up to the job anymore. I have a budget which includes the sale of my old one. I can afford to either: a) Buy the current 15" rMBP without the dedicated nVidia card (so Iris Pro only) -or- b) Buy the late 2013 model with the gt650m with 1gb gddr5? Both around the same price. I used to just shoot, edit in FCPX and render 1080p but these tasks in my 2012 rMBP are just long and drawn out affairs especially rendering. I potentially need something that will be futureproof to a certain degree, perhaps even involving 4k footage. Is the Iris Pro in itself capable of any of these tasks at a reasonable pace? Or should I look at the dedicated 650m? 1gb of ddr5 doesnt seem a huge enhancement over Iris Pro.