[SOLVED] Downscaling vs Upscaling of Screen Resolution.

[Elros]

Hello.
I was connecting my 4KTV to my laptop yesterday, and VRAM wasn't enough to run on 1440p for the specific game, RDR2, so I had two options to tweak and get 30fps,

1- Upscale the resolution to 1440p via AMD VSR while running 1080p native desktop, then set the screen resolution to 0.7(7/10).
2- Use native 1440p for both in-game and windows, then downscale the picture to 0.7(7.10)
Use sharpening for both solutions.

So, I didn't have my glasses on, but the performance and quality seemed the same to me, however, I really would like to know how downscaling and upscaling technology works.
Is it always better to run on native resolution and then start from there? Or just like in solution 1, rendering at 1080p and then upscaling it to 1440 but reducing the upscale resolution would be actually better? (kinda like fake DLSS2.0)

Thanks and Regards!

 

[k1114]

VSR is not upscaling, it is running the game at the higher res and downscaling. Desktop res is overridden by fullscreen. So in both situations, the game was running at 1440p and since it's a 4k tv, it didn't downscale. I don't know what screen res setting you are talking about but a render res setting in game will run the game at a lower res but can possibly keep ui at the higher res. It's no different than setting the game at a lower res other than the ui being rendering at a higher res than the 3d graphics if the game is set up that way. Upscaling has no performance impact. It is just taking the image and stretching it to fit fullscreen. Downscaling runs at the higher res so has the same amount of resources used regardless of monitor res but just squeezes the image to show on a smaller res which has the same effect as SSAA. Since the tv is 4k, you are not downscaling unless you set the res above 4k.

 

[Elros]

VSR is not upscaling, it is running the game at the higher res and downscaling. Desktop res is overridden by fullscreen. So in both situations, the game was running at 1440p and since it's a 4k tv, it didn't downscale. I don't know what screen res setting you are talking about but a render res setting in game will run the game at a lower res but can possibly keep ui at the higher res. It's no different than setting the game at a lower res other than the ui being rendering at a higher res than the 3d graphics if the game is set up that way. Upscaling has no performance impact. It is just taking the image and stretching it to fit fullscreen. Downscaling runs at the higher res so has the same amount of resources used regardless of monitor res but just squeezes the image to show on a smaller res which has the same effect as SSAA. Since the tv is 4k, you are not downscaling unless you set the res above 4k.

Thanks for the answer!
There is an option in the game settings of RDR2, which is called "Resolution Scale" and the explanation on the web is this:

"Players can alter the in-game rendering resolution using this setting while still outputting the result at the native resolution of their display. The scaling works both ways. If your native resolution is 1920x1080p, setting this option to 0.5 would result in the game being rendered at 1280x720p and upscaled to 1080p. Setting the option to 1.5 would result in the game being rendered at 2560x1440p and downscaled to 1080p."

So I did that. I did run both the game and desktop on 1080p resolution, and then adjusted settings to medium, and did set the game resolution to 1440p(VIA VSR, because desktop was still on 1080p) and used that above solution and made it render the game x1.5, which technically means that the game renders itself on 2k and downscales it to 1k I assume, with sharpening it also looked way better than native 1080p on 4k TV.

And then I set both the game and desktop resolution on 1440p, and then adjusted the in-game "Resolution Scale" option to x0.75, which is technically the game is being rendered at a lower res than 1440 but then upscaling it to 1440p, so It's worse than 1440p but better than 1080p I hope.

Both did look the same to me and the performance was the same as well.(I had to tweak settings in both just to get enough VRAM and 30 fps, so didn't take screenshots since everything was messed up)
So, I wonder which option is technically better? Running the game and desktop on 1440p and then downscaling via game resolution scale?

 

[k1114]

Desktop res is irrelevant. The in game settings overrides it. When you set vsr to 1440p, the in game res option should show 1440p so you are at 1440p not 1080p. If the in game setting still shows as 1080p then vsr is not on and you are at 1080p.

Using res scale in game is the same thing as just lowering the game res setting. The only difference is the ui is not affected which shouldn't really do anything for fps. Vsr gives the options for higher res than native but since the tv is 4k, it's not doing anything at all when you set it to 1440p other than a sharpening filter.