Samsung 50" led tv refresh rate problem

[Svrco]

hello guys, I have a problem with my samsung 50ku6072 tv when i connect it with hdmi to pc
so on my amd graphics settings it say: Max resolution 4096x2160 and Max refresh rate 75hz.
BUT when i pick that resolution i get 30hz but when I do 1920x1080 I get 60hz I want to know how can I raise that refresh rate at 4k resolution so i can play games. Please help! tnx

 

[Barty1884]

Which GPU do you have? Sounds like you're dealing with HDMI 1.4 on either your GPU or TV (or both).

HDMI 1.4 supports 4K up to 30Hz (hence the results you see)

HDMI 2.0 supports 4K @ 60Hz and 1080p @ 144hz

 

[Svrco]

Which GPU do you have? Sounds like you're dealing with HDMI 1.4 on either your GPU or TV (or both).

HDMI 1.4 supports 4K up to 30Hz (hence the results you see)

HDMI 2.0 supports 4K @ 60Hz and 1080p @ 144hz

I have hdmi2.0 on both and gpu and tv but its connected throu hdmi1.4 cable, so your saying that i shold buy 2.0 cable?