Ratio of the matter power spectrum at z = 0 for different starting redshift z_ini (in coloured lines), with respect to a reference simulation with z_ini = 150. We use 1LPT, 2LPT or 3LPT initial conditions from left to right and three-, five- and seven-point gradients from top to bottom panels. We use the FFT solver in any case (see Section 3.8). In each subplot the top and bottom panels show simulations which use TSC and CIC mass-assignments schemes respectively. Grey shaded area denotes a 1% discrepancy w.r.t. the reference power spectrum.