Hi guys, I'm about to purchase a new imac. My primary requirement is for 4k video editing for work, I will work with short clips editing 1 minute ads for a local company. Footage is shot off my GH4 and mavic pro. I have two options with apple employee discount. 1) base 3.4ghz with 512gb ssd upgrade 2) refurbished 3.8ghz with radeon 580 8gb, 2tb fusion drive Both would come in at the same price more or less. I am curious if the processor and better gpu would outweigh the fusion drive. If I understand correctly there will never be a way to upgrade the fusion drive to an apple ssd in the future?