  We investigate how thermalization of gluons depends on the initial conditions
assumed in ultrarelativistic heavy ion collisions at RHIC. The study is based
on simulations employing the pQCD inspired parton cascade solving the Boltzmann
equation for gluons. We consider independently produced minijets with $p_T >
p_0=1.3 \sim 2.0$ GeV and a color glass condensate as possible initial
conditions for the freed gluons. It turns out that full kinetic equilibrium is
achieved slightly sooner in denser system and its timescale tends to saturate.
Compared with the kinetic equilibration we find a stronger dependence of
chemical equilibration on the initial conditions.
