Hi there, I am new to mac and coming from PC with i7. I looking at buying an imac for home office and looking at future proofing it. It is more for personal media music photos movies etc. I was looking at 21.5 but realized you can't upgrade the ram later so now looking at the 27 inch although I would like to use 1tb ssd and not sure if I need to upgrade to i7. The bulk of my media music etc will be stored on a NAS drive and just have my MS Office as well as OS and apps on the ssd. Thoughts ?