The time taken by each code for the syntheses in Section 3. Top: average compute time for the optical wavelength regions, which used very dense line lists. Bottom: compute time to synthesize spectra from 15000 to 15500 Å with the APOGEE DR16 line list, a more “realistic” use case. Note that the wavelength regions synthesized were larger than those plotted in Figures 5–8. SME includes a true scattering treatment that cannot be turned off, increasing its execution times.