Question: what is 5k vs 4k?
Answer: A true 4K display has a resolution of 4,096×2,160 pixels, but most 4K displays you will find are actually "Ultra HD" displays with slightly lower 3,840×2,160 resolutions -- sometimes called 2160p. 5K displays have a resolution of 5,120×2,880 pixels, or about seven times the pixel density of a 1,920×1,080 display.