I'm looking to purchase a 2015 iMac, and one of the intended uses will be to edit some videos for personal use -- mostly small stuff, possibly something mid-sized. I recently purchased FCPX, but have not had a chance to use it much yet. I currently only shoot 1080p/60 video, but can see that in a couple years I will probably be shooting 4k. I've read multiple posts recommending 3 disks -- 1 for OS/Apps, 1 for raw Media, and 1 for the working files/cache/etc. Given the crazy fast speeds of the internal flash/SSD, is it reasonable is it reasonable to combine the OS/Apps with the working files/cache/etc on internal flash/ssd (1TB), instead of having two drives? I prefer a simpler setup, if it can function well. Thanks in advance!