21:9 vs 16:9 fps difference

Solution
LG 34" Ultrawide owner here. If you want to play games at a regular 1920x1080 res with black bars on the side you will need to ensure that the aspect ratio on the monitor is set to 1:1 and not Wide. By default it is set to wide which trys to stretch everything out.

Lots of games still don't fully support the 21:9 Ratio like Dota 2 leaving you with no choice but to play with the black bars on the side (which isnt reallly an issue in my opinion)
But most games that I have played seem to run fine. You do get like 20%-25% less performance because you nearly have 30% more pixels (If comparing 2560x1080 to 1920x1080)
2,764,800 Pixels vs 2,073,600 pixels. So you'll lose about ~25% FPS depending on the game you are playing.
If you were getting 100FPS before you'd get 75FPS, or 60 FPS before 45 FPS after.

All theoretical and varies game to game.
 


one more qustion if i get the 21:9 which i probably will if i turn down the resolution to 1920 will it look the same as a regular 1920x1080 monitor or will it be messed up im just hitting 60fps in games so dont wanna get ultrawide and get 45 my gpu is a 780ti thats why im asking
 
resolution can be turned down, but so can the settings in the game as well. you don't have to run it at max settings to enjoy the game.

what gpu is it you have? can probably search out some benchmarks for that resolution anyway to get a better idea what performance to expect.
 


kingpin 780ti at 1250mhz
 
You can change the aspect ratio, but on a 21:9 screen, 16:9 would look like utter garbage.
You'll have these black bars on the sides of your monitor, covering half of your screen.
It's a lot better to turn down graphics, most games today, even at lowest settings look utterly stunning.
 
LG 34" Ultrawide owner here. If you want to play games at a regular 1920x1080 res with black bars on the side you will need to ensure that the aspect ratio on the monitor is set to 1:1 and not Wide. By default it is set to wide which trys to stretch everything out.

Lots of games still don't fully support the 21:9 Ratio like Dota 2 leaving you with no choice but to play with the black bars on the side (which isnt reallly an issue in my opinion)
But most games that I have played seem to run fine. You do get like 20%-25% less performance because you nearly have 30% more pixels (If comparing 2560x1080 to 1920x1080)
 
Solution
I got curious too , i have been gaming on a 2560x1080 instead of a 1920x1080 resolution, did a benchmark on Rainbow Six siege and the fps for 21:9 is average 93 and 16:9 is 126, it might be a huge difference to some but it is not that bad to get that extra vision view, my system i used (i7 7700, GTX 1060 6GB, 16GB DDR4 RAM)
 


Not really tbh, i play csgo on 16:9 on a 21:9 screen, the only thing is that the brightness is somewhat brighter.