Fit borderless game into a screen with different resolution

[n0ns3ns3]

I have a 3440x1440 monitor as my main screen and another 24" as a secondary.
I like to play games in borderless windowed mode to easily multitask.
For some games, i'd like to set the render resolution to 2560x1080, but than the game is not filling the whole screen unless it's set to full scree.
The question is: how can I have the game using lower resolution than the monitor running in a borderless windowed mode and yet filling the screen?

 

[madmatt30]

You can't unfortunately , the window will be rendered at your desktop resolution so it will only take up the relative pixel size.

The only way you can do this is to change your actual desktop resolution to 2550x1080 before you start the game & switch it back when you're done

 

[n0ns3ns3]

that will resize other applications as well.
the thing is that if i pick windowed mode, i can resize it. but not in borderless mode. So i guess technically it should be possible.

 

[madmatt30]

that will resize other applications as well.
the thing is that if i pick windowed mode, i can resize it. but not in borderless mode. So i guess technically it should be possible.

You'd like to think so but it honestly isn't.

You're not the first person to ask this question or want to do this.

 

[n0ns3ns3]

there are some 3rd party programs that manipulate undesirable windows. unfortunately does not work with all games.