Black Borders when using native resolution

Hello all:

I am attempting to run Hardline with my native resolution of 1920X1080. I have selected the correct resolution in the options menu as well as "fullscreen" but it continues to run with a sort of "letterbox" with black margins around the screen. I can select "borderless" and it seems to fix the issue, but causes somewhat of a performance dropoff. Any help would be appreciated. Thanks.