We reduced the computational cost first by using a more inexpensive method to compute energies and avoiding structure optimization. We recreated the QM9-based synthesizability test using two methods which require only CPU seconds to compute the energy of a molecule: the MMFF94 forcefield and xTB. As shown in Fig. , MMFF94 achieves a classification AUC of 0.62 -far less than the performance of either G4MP2 (0.82) or B3LYP (0.84). In contrast, the performance of xTB is comparable to G4MP2 with a AUC of 0.79 when we use the energy of a geometry optimized using xTB. We can further reduce cost by using MMFF94 for geometry relaxation instead of xTB, and find this approximation does not reduce accuracy either (AUC: 0.81). Using xTB reduces the computational cost for the energy of a single molecule from hours to seconds without significant loss of classification accuracy.