Oh well I made a bit of a compromise, put my GFX quality on medium but I have to live with degraded FPS in a huge firefight, and 75% render.
Infiltrators are a complete joke on this setting. It's just weird, like a "KILL ME I RUN HERE" sign is above them or something.
Hope they come up with a solution for infiltrator update, so SMG infils can't farm people with bad computers