Ultra wide monitor (21:9) not working properly for MW3

[Shriabee]

Anyone knows how to let the game run at 21:9?
My monitor is at 3440x1440p (recommended). But when i enter game, it looks like 16:9 with blank borders on both side. I installed the newest driver from nvdia. I tried change resolution and change the in game aspect ratio but nothing works ( only at 3840x2160p the game can fill my screen but obviously stretched). When i try auto resolution, the game became super blurry with minimal res…
I use 13700kf+4080. Shouldn’t be HW issue…

[deagle44mag]

try changing from full screen to full screen borderless

[djcarey]

Try 32:9

[A Lonely Prince]

Works for me no issues.