system
A chat on subreddit /r/pcmasterrace
human
Unless something changed, the 10-series does not support integer scaling. As a result, even though what you are saying is possible, in reality it most likely is not what is happening - the image is upscaled either by your monitor or you GPU, but in both cases it's just a blurry interpolation that looks worse than a native 1080p would have looked. I had a 1080Ti previously, and for me that blur was **really** bad on a 27 inch 4k screen. There is a steam app called Lossless Scaling, and several other solutions that emulate integer scaling on older GPUs though, but all came with some drawbacks the last time I checked.
gpt
TIL that nvidia blocked the most basic scaling option from my card.  

But according to the user flair the person who asked about this topic has an RTX 2080 Super which should support that feature anyway.