Sorry boys this comment (Are you both saying there's a slight possibility it's not true? ) was just my sarcastic sense of humor, didn't mean to stress anyone out.
I'm pretty sure HDMI 2.0 should run 4K @60hz, If you haven't already, id try another HDMI 2.0 cable just to make sure the one you're currently using isn't 1.4.
It doesn't automatically upload for me, not sure if that's because I use Firefox, but when I paste the link I get the message (paste as plain text) I click on that and a couple of seconds later it shows the tweet.