Q: I GET TERRIBLE HORIZONTAL FLICKERING LINES WHEN TURNING.
Q: I GET SCREEN TEARING, EVEN IF I PRESS F10 TO TURN HIALGO OFF...
You see tearing, because by default HiAlgoBoost turns VSYNC off (to get better performance). In most cases the tearing is hardly noticeable, but if your framerate is around 60fps, it may be annoying. In this case set NO_VSYNC to false in HiAlgoBoost.ini.