For the 55" Sony, it support HDMI 2.0 - but no displayport, so you need a HDMI 2.0 video card - which means the latest gen - like the GTX 970/980.

Otherwise you'll have to use 4k at 30Hz, which absolutely sucks for games. I already have a 4k Dell 32" monitor and at 30Hz it's horrible. I figured out how to use DP to get it to 60Hz and it's pretty sweet. I use it on my mac now.