I'm a commercial photographer who also dabbles with video. I have produced a few short promotional films for clients as well as doing some broadcast press coverage. I hope to develop this further and push this service to some of my larger clients so have been looking at upgrading my editing hardware with view to moving to 4K over the next 12 months. I'm considering a 5K iMac with as much ram and graphics memory as I can get, but am unsure of which way to go with storage. I currently run a Mini with an SSD startup drive with a second disc for files. The iMac has only one drive space which looks pretty complicated to change. I'm considering a 256MB SSD internally for OS and Apps and then an external drive for files but I'm concerned that this won't be fast enough for editing and playback of 4K. Should I use Thunderbolt, SSD, a Raid 0 system or is a good USB 3.0 drive fast enough? Or would I be better off with a bigger internal drive to use for the files I am working on and then archiving them when I'm done?