I'm planning to upgrade from my 2011 iMac to a new one, 2017. I mostly do Lightroom and Photoshop, but I'm starting to edit video. The 2011 iMac has a boot drive and a second internal drive, and I've been putting the video clips on the internal drive. Everything else - Lightroom and backups - are on external drives. I was thinking I should get either a 500GB or 1TB SSD drive to handle the video editing. But do I want all of that on the boot drive? Would it be better to get an external SSD for video, given that it'll have the USB-C ports? Then I could easily get away with a 500GB SSD, or even 256GB. So far I don't have much need for 4K recordings, and the destination is youtube where I think 1080 should be fine for quite a while. I plan to upgrade from iMovie to Final Cut Pro though. Appreciate any advice. Thanks.