Yes! You can really play 4K or UHD content on your FHD screen even when it is not compatible. You don’t have to go through hard trouble too. Just play the content on your FHD screen and it will play it. And if you want to know how it plays that content even when not compatible. Then you should know about the process known as downscaling. With the help of downscaling it is able to modify the content to FHD level, that is 1080p. But this process will affect the quality of content and the quality that will be served to you is not actually 4K. You will get the 1080p (although it looks finer than that.)  Similar to this there is also a process called upscaling. With it, you can play lower-quality games such as FHD on your 4K or higher screens. But here it will seriously affect the quality of the content. You will view a little blurry content but you will have to make this sacrifice for viewing. We are familiar with both these processes but not aware of them. Our smartphones use them whenever we play something that is of high or low in content quality.