Need to know which configuration of iMac to get. I do photo editing and some video editing. I keep my computers for a really long time so I kind of want the closest to the best I can afford right now. I want the 27" iMac and am considering getting the core i7 model or is a core i5 model good enough for my needs? Does it matter what graphics card I get? I can install the extra memory myself. Which Fusion drive should I get, the one or two TB? Does that make a difference in speed? I just don't want to end up with any spinning beachballs because they drive me mad. Thank you, sorry if my questions sound dumb, I'm no computer expert.