PIE Resolution Scale - HELP

Hope you can help me with my problem.
When I want to just run through the level I built and click Play In Editor (PIE), resolution downscales to nearly 800x600 and it’s really hard to see how textures blend from character view.
I tried going to “Play In Editor Settings” and set higher resolution there. But that didn’t do anything.
So now i don’t know what to do with this.