I recently discovered when I bought a 4K display, that HDMI cables don't cut it, you must have DisplayPort to get over 2048 pixels wide. While I ran a cheap backup card, I was subjected to 30hz refresh rate (not the flicker rate, just the screen change rate) and 60hz is better but I want 240 or faster, and more, 480, if I am using VR. The processors we have now, it would take about 50 of them to generate the scene at that framerate. So you see how high the ceiling is...

Until you have got used to 60+ frames high res game graphics, you don't realise how much even as low as 40fps can kill interactivity and precision reflex responses. Then with that in your mind, watch some movies and notice how they constantly have to stick to certain shots and revert to slow motion to capture the impact of action that you could see well enough if there were more frames per second.