How many displays can 5k iMac push? Purchased one today and learned this: 1. Can't push (2) additional 4k monitors only 1. 2. Cant seem to push 27" Thunderbolt display + 4K either. 3. Was able to get it to push a 720p display for a second, but wasnt able to get to do it consistently. Sorry if this has already been covered, but is 1 additional monitor all this guy can push? ---------- Perhaps can run 2 (27) thunderbolts and no 4k monitor... Think the 4k montior is killing the equation.