Hi there, I'm looking to buy a new high-end 21.5" iMac with a 256GB SDD drive to run my OS, apps and working files. Hoping to put my Photos library on an external HD and when I launch Photos, have it store media on the external drive. Will Photos have enough speed so that it feels really fast, or will I take a performance hit having the media on an external drive? Anyone have experience with this sort of workflow? Which drive do you have? What drive would you recommend? Hoping to have about 2TB of external storage. The Samsung SSD external would be nice, but out of my budget. Will it make a difference if the drive is Thunderbolt 3 vs USB 3.1 or USB 3? I'll have the external drive I buy back up to an existing WD 3TB USB 3.0 drive. Down the road, will look at spending bigger bucks on a Thunderbolt 3 RAID of some sort. TIA for any advice!