Using Gears of War 4 on Xbox One S and PC as an example, the following video aims to show the differences between 1080p, upscaled 4K and native 4K. However, to get the full benefits of the differences its recommended that you view the video in 4K (by selecting the cog on the player) on as large a screen as possible. Laptops or mobile phones make it quite difficult to see any differences. Something else to consider is to focus on specific areas of the screen or objects such as foliage detail in the foreground. Watching the video on a 4K TV and its quite clear 4K has a massive edge over 1080p but everyone sees things differently, so can you spot the differences in visual quality between 1080p vs 4K even when viewing on a 1080p screen?
[Source: cramgaming.com ]