I am currently using direct3D10 (hardware), it's faster than (software) but it also causes vertical black lines to appear on the image of my game. I switched it to direct3D9 (hardware) but it's still the same. The (software) option make the lines disappear but it's laggy.
I am just wondering whether it's normal, anf if not whether there's a way to fix it.

   

set internal res to native

It worked! Can't believe that it's so easy. Thank you so much!