UHD / 4K screen blurry in FHD mode

A UHD display is 3840 x 2160 and FHD is 1920 x 1080. For every one pixel in FHD there are four pixels in UHD as the horizontal and vertical counts are double.

I would then expect to be able to tell Windows / apps / games to switch to 1920 x 1080 and see a perfect picture, albeit FHD. This is because there is no interpolation, simply a straight mapping from 1 to 4.

But the display is a big "soft", blurry, and it does not appear as crispy clear as on the native 4K resolution.

Could someone please explain why that is?

 

This is exactly why I tell people never to buy a 4K screen on a laptop! At the native resolution, you can't see anything without using a magnifier, so then you'd have to do DPI scaling or lower the resolution only to get a blurry display and misaligned buttons/text in apps that don't properly support DPI scaling! So why get 4K in the first place? just to tell people that you have the latest and greatest 4K screen which you can't even use?

How does anyone in his right mind buy a 4K screen laptop?

 

Thanks for your reply but I do not think you have understood my question so I will try to explain. My desktop runs at 4K and I have 200% on Windows and it is crystal clear and I would never again go back to FHD. I can post photos if you like, and what you say about blurry display is absolutely not true. I am typing now this at 4K/200% and I have never seen a clearer display in my life.

In gaming because the GTX 1080 can not keep up at 4K in some games and we get like 40-50FPS, as a quick solution we thought to set the game (PUBG, or WoW) to some lower resolution, eg FHD. But when we do this things appear a bit more blurry than they ought to, and I wonder why. Since in Windows the screen is very clear I know it is something that happens when you go gaming fullscreen mode in a different resolution than native, but I would like to know the technical reason.

 

Ahh ok now I get it.

Well the thing is, LCD Monitors only show you crystal sharp images/text when they're run at their native resolution, any other resolution will result in a blurry display. We don't have the freedom of changing resolutions like in your case to get better performance like we did in the old days of CRT monitors

See: Why You Should Use Your Monitor’s Native Resolution

Also from reddit forums:

 

Again thank you for your reply. However in the case of UHD/FHD the ratio is a perfect int, so like the mosaic tiles example above we do not have a " 50 x 50 and 30 x 30" situation but instead, we have a "50 x 50 and 25 x 25" situation. That means I can use my 25x25 tiles in a bathroom designed for 50x50 tiles and I will use 4 of 25x25 tiles for each of 50x50 tile and it will be perfect. I hope you see what I mean.

 

https://forums.geforce.com/default/...equest-nonblurry-upscaling-at-integer-ratios/

This might explain the issue.

https://amp.reddit.com/r/nvidia/comments/akqosn/there_may_be_hope_for_integer_scalingnearest/

 

Thanks very much for the links, but it does not explain the issue other than reading through 67 pages of comments dating back many years from frustrated users, like me, who cannot understand why integer upscaling is not perfect.

 

From reading, it seems Nvidia and AMD didn't bother to implement integer scaling, even after much demand. That's why the blurriness between 1080p and 4k.

There is a integer scaling software for windowed games, I can find on steam but I have never used it.

https://store.steampowered.com/app/993090/Lossless_Scaling/

 

My 4K display looked beautiful at 150% scaling except for a few apps. It also had the same issue.

My 4K TV when connected to my nintendo wii u didn't look as sharp as 4k native but looked very good regardless.

I think most people just aren't implementing it

 

People have already answered your question but you're rejecting the (correct) answer.

You will see a blurry image regardless of whatever you have in your head about perfect scaling because..... you're scaling. if everyone could run 4k panels at 1080p and call it a day they wouldn't need new RTX cards that can run at 4k above 60 fps.

Anything less than your panel's native resolution will look blurry. end of. rest of what you told yourself when you bought the 4k screen was wrong. now you are realising it.

Its blurry, which is why you came to post it. Get a 1080p panel, or run at 4k, and it wont be blurry.

 

Maybe you ought to do some research before alluding to "what I told myself when I bought a 4K screen".
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The "correct" answer as you said, lies in :

https://forums.geforce.com/default/...request-nonblurry-upscaling-at-integer-ratios

hint1: the clue is in the word, "integer"

hint2: can be done in software, can be done in static displays by anyone, where it lacks is to be done in hardware like all other modes so it is quick

 

People that don't know things will bash a product assuming it supposed to work the way it is for everyone.

I remember the 4K 1080p 1:1 mapping hype and that was the reason I went 4K.

It's saddening nvidia doesn't implement such a nice feature.

 

Frustrating that this issue is exactly the same status as when it first came up about 4 years ago. No real progress from microsoft or nvidia about making 4k more practical.