PS4 and Xbox One don't have 4K capabilities, pretty bad for "next gen" consoles, most people that want a 4K gaming experience usually switch to PC as that's the only way to get true 4K gaming nowadays, but it costs a lot to get a decent framerate on 4K, a happy medium would be 1440p which is 2.5K which is more manageable, UHD TV'S are still able to play 1080p and you will see improvements to ps4 native output as TV's upscale pretty well.
that's a bit rubbish for my new PS4 would using pc monitor make things better ? or is that what u meant ? ..... is that hdmi to vga or dvi ?
Not really, the displays all produce the same image regardless, it just depends on whether the software does a good job of cleaning up the image.
It's still irrelevant if the image is via VGA, HDMI or DVI, 4K can only be produced on high bandwidth cables, HDMI 2.0 or display port.