First we evaluated our GROMACS implementation of C36/LJ-PME by comparing the area per lipid of DPPC bilayers at di↵erent temperatures with the data from the original C36/LJ-PME publications, our standard C36 simulations, and with experiments (Fig. in the SI). All simulations give consistently slightly lower area per molecule than experiments for DPPC bilayer at 333 K. However, at 323 K, C36/LJ-PME simulated with GROMACS goes into a ripple phase and gives significantly lower area per molecule than when simulated with OpenMM. More condensed membranes and higher melting temperatures have been reported also previously from C36 simulations with GROMACS and leap-frog integrator than from OpenMM and Langevin integrator. In Fig. in the SI, we demonstrate that switching to Langevin integrator in GROMACS can melt the ripple phase in DPPC bilayer at 323 K, suggesting that integrators are the source of the di↵erence. For more detailed discussion on the bilayer results, see SI. We conclude that our C36/LJ-PME GROMACS implementation with leap-frog integrator behaves well in temperatures that are not close to phase transition temperatures, similarly to the regular C36 GROMACS implementation. ) and with di↵erent water models in this work. Additionally, data for the standard C36 simulated with OPC4 water, taken from our earlier work, are shown together with experimental data extracted from well-equilibrated monolayers. To test the performace of C36/LJ-PME in monolayer simulations, we compared the surface pressure-area isotherms of DPPC and POPC monolayers with the isotherms from standard C36 with OPC4 water from our previous work and experiments in Fig. .