Silicon Graphics has sued ATI, claiming the graphics chipmaker infringed a computer-graphics patent that ATI's competitors have licensed. Patent No. 6,650,327, filed in 1998 and awarded in 2003, involves describing graphical elements with floating-point numerals to balance the range and precision of values that can be stored. If the SCG lawsuit is found legit, that means any DirectX9 based gfx chip manufacturer is liable if they do not have licensed the technology.