Matter power spectrum ratio between a 0.15 eV massive neutrinos simulation and a ΛCDM simulation with varying timestep, performed by ANUBIS. The simulation box has L_box = 1024 h⁻¹Mpc, N_cdm = N_ν = 1024³, and a fixed coarse base grid of 512³. The time step is calculated by the RAMSES algorithm for both runs, but for the ΛCDM case it is multiplied by a reduction factor, A. We see here that one way to compensate for the coarse base grid, especially at large scales, is to shorten the time step. This requires a longer run time for the ΛCDM simulation, but not more memory as would be the result of adopting a finer grid.