  The octahedron model introduced recently has been implemented onto graphics
cards, which permits extremely large scale simulations via binary lattice gases
and bit coded algorithms. We confirm scaling behaviour belonging to the 2d
Kardar-Parisi-Zhang universality class and find a surface growth exponent:
beta=0.2415(15) on 2^17 x 2^17 systems, ruling out beta=1/4 suggested by field
theory. The maximum speed-up with respect to a single CPU is 240. The steady
state has been analysed by finite size scaling and a growth exponent
alpha=0.393(4) is found. Correction to scaling exponents are computed and the
power-spectrum density of the steady state is determined. We calculate the
universal scaling functions, cumulants and show that the limit distribution can
be obtained by the sizes considered. We provide numerical fitting for the small
and large tail behaviour of the steady state scaling function of the interface
width.
