I was too until reading about multicord setups to make 5k work. > If you bought Dell’s 5K monitor, which has the same 5120x2880 resolution, and connected it to

I was too until reading about multicord setups to make 5k work. > If you bought Dell’s 5K monitor, which has the same 5120x2880 resolution, and connected it to your Mac Pro, you’d need two DisplayPort connections for its two TCONs. If this iMac were just a display, you’d only need one connection—but of course it’s a whole computer, so you need zero. Additionally, Apple's support page mentions this.