4:3 stretched not working

[you like clicking heads dont you]

im having performance issues because of my not so good pc and since ive played a bunch of fps games and really like the 800:600 stretched res i decided to try it in phasmo but even with full screen scaling and override application settings or whatever turned on theres still black bars, anyone know why? it works on tf2 and cs so i dont see why it doesn't here