Alternatively, the significantly more efficient forcefield method GFN-FF 53 can be used, and the conformer search be accelerated using the 'quick' setting in CREST (herein termed conf2). For 100 randomly selected molecules, Fig shows a comparison of λ GFN1 values for the lowest-energy conformers obtained with conf1 and conf2. While the bulk of the predictions falls within the error margins of ± 20 meV, we also find 16 outliers -marked in orange. These can be attributed to an incomplete coverage of conformational space in the conf2 ensemble and to differences in the energetic ranking between GFN1-xTB and GFN-FF.