  We identify hardware that is optimal to produce molecular dynamics
trajectories on Linux compute clusters with the GROMACS 2018 simulation
package. Therefore, we benchmark the GROMACS performance on a diverse set of
compute nodes and relate it to the costs of the nodes, which may include their
lifetime costs for energy and cooling. In agreement with our earlier
investigation using GROMACS 4.6 on hardware of 2014, the performance to price
ratio of consumer GPU nodes is considerably higher than that of CPU nodes.
However, with GROMACS 2018, the optimal CPU to GPU processing power balance has
shifted even more towards the GPU. Hence, nodes optimized for GROMACS 2018 and
later versions enable a significantly higher performance to price ratio than
nodes optimized for older GROMACS versions. Moreover, the shift towards GPU
processing allows to cheaply upgrade old nodes with recent GPUs, yielding
essentially the same performance as comparable brand-new hardware.
