The time to generate the FG-dataset and train the GNN is 10 5 s and the evaluation of the larger molecules is 10 -2 s. Thus, for a single comparative DFT vs. GNN evaluation, the gain is several orders of magnitude (likely 6-10 depending on the size of the big molecule) while the grey hidden cost of training the network is 10 5 s. The positive part is that once trained, the GNN structure can be widely applied to other compounds.