LG 34UC79G CRU custom resolutions

[Jase]

My monitor is an ultradwide with a resolution of 2560x1080 at 144Hz. I used CRU to set a custom resolution of 3440x1440 at 100Hz( failed at 144Hz). I thought is was supposed to downsample the 1440 to 1080 so everything looks like 1080 only sharper. But if I run, for instance, Borderlands 2 in window mode set to 2560x1080 while windows 10 is set to 3440x1440 the game takes up a fraction of the screen even though I would expect it to fill the screen if it is being downsampled. Running full screen though with both resolutions the 1440 was clearer. I looked some info up on CRU and apparently it will scale up but not down so now I don't know what is going on or if it is worth it to run the custom resolution. FWIW I was doing all this to get around AMD's perpetually broken Virtual Super Resolution.

There is some other weird stuff as well. If I change the resolution from 1440 to 1080 with aspect ratio preserved the whole screen pulls in a little instead of staying put. Sort of like when I set it to 1920x1080 and end up with huge black bars on either side just less extreme. If I use centered instead of preserve aspect ratio then 2560x1080 shrinks way down. Anyone know what is going on or how CRU works? I don't think I am understanding it correctly.

[Dals | Thalita's Wife]

Let's be clear, why do you have to set a custom resolution for your monitor? 2560 x 1080 is supported by most games...

[Jase]

I am trying to do a ghetto version of Dynamic Super Resolution (http://techreport.com/review/27102/maxwell-dynamic-super-resolution-explored). Basically the gpu renders an image at a higher resolution than the monitor supports and it gets downscaled to fit the monitor creating a sharper image. I have an AMD card and their version, Virtual Super Resolution, has been broken for many months. So I was curious and attempted to do something similar in theory with the few tools available. It's not practical because even the real methods of doing this use a massive amount of hardware resources but I was bored and I like tinkering. The problem is nothing is behaving like I would expect it to. It is sort of acting like the native resolution actually is ultrawide qhd but I seriously doubt LG is throwing very expensive panels into cheaper models and hiding higher supported resolutions. I am hoping someone with more knowledge can explain what is happening.

On a hunch I completely removed the custom resolution, reset everything and 2560x1080 went back to filling the entire screen. There is some unknown source of scaling it seems. I think that without driver support or some sort of post-processing scaler built into the monitor (remotely similar to what UHD tv's attempt to do with lower resolution content) there is no way to downscale the image and increase sharpness. Oh well.