My 2011 macbook pro is not cutting it anymore. I am looking at buying a new 27" i-mac, fairly soon. The main use for this new machine will be for me doing a lot of 4k video editing probably using Final Cut Pro X and already do a lot of raw image photoshop CC/Lightroom editing work. I need feedback from those who have used and or are in the know please. I am trying not to spend the $$$ on the highest imac if possible. Considering what i have listed for use, how much of a difference will an i7 processor make over the i5?. Then how about the performance difference in graphics cards from the R9 M395 vs. the 395x? I would like to start with 16 gb of RAM and a 1 TB SSD drive. I am trying to get a machine that will stay speedy and up to the task of editing lots of 4k video files for a few years. I have been looking at refurbished i-macs from the Apple site, but as of yet have seen the one i want. Please let me know what you think of the processor differences and graphics card differences for my listed above intended use, thanks in advance for the help.