I plan to buy a new iMac with a 256k SSD internal hard drive and move pix/videos/media to external hard drive. I don't need large size external... 1TB would be fine. I am torn between getting Samsung T5 SSD which uses USB-3.1 and any other manufacturer SATA HDD connecting with Thunderbolt 3... unfortunately the combination of SSD and Thunderbolt 3 is cost prohibitive. So what is more important in terms of speed/performance... SSD drive or Thunderbolt 3 connectivity?