Seems a lot of people won't be satisfied until it renders in 1920x1080 and downscales it to 1920x800 to get the correct aspect ratio, which wouldn't look as good as using a 1:1 pixel ratio.
You don't just add black bars to fix performance issues, aspect ratio affects how most of the game is build. Same way you can't simply add black bars to make a 4:3 show, 16:9. The composition is then ruined. A correctly done 2.4:1 aspect ratio has a higher load on the rendering engine as more geometry is in view due to the wider field of view.
To repeat my example again, which image has a higher load on the rendering engine:

You save 26% of pixels that have to be rendered, but you end up rendering 35% more geometry. Rendering less pixels definitely helps, but if you've tinkered around with fov on pc games you probably know that increasing the fov can have a substantial hit on performance.







