Compute time for lightcones from z = 35 to z = 6 at various box sizes using two threads and a 2 Mpc cell size. Blue: Previous source model of 21cmFAST (see ‘v3 Default’ runs in Section 6 Orange: Runs with a non-stochastic source field (see ‘CHMF on grid’ in section 6). Green: runtime for the halo sampler using a minimum mass of 10⁸ M_⊙. Red: Runtime for the halo sampler using a minimum mass of 10¹⁰. The new filters described in section 4 and the halo sampler at 10⁸ M_⊙ each add approximately 50% to the runtime, compared with the gridbased model.