| 1:31:57 AM PDT - Wed, Apr 1st 2015 |
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NWChem may be doing a little extra work if you use default tolerances in both programs: https://getd.libs.uga.edu/pdfs/papas_brian_n_200605_phd.pdf
The DFT accuracy comparison there shows that NWChem settings tend to a bit higher accuracy than Gaussian for DFT.
There may be some speedups possible but I don't think you are doing anything particularly wrong to see these slow results with NWChem. Gaussian runs very efficiently on small computers, with the disadvantage of poor parallel scaling.
NWChem's price and openness can't be beat but I would not expect it to best Gaussian on execution speed except for large calculations on large parallel machines. I use it on small machines nonetheless because its capabilities are rich, I don't need to advise other people to ask for software licenses to reproduce my results, and I find its input syntax far more sane than Gaussian or GAMESS. If you already have Gaussian licenses then you needn't worry about the expense, and Gaussian is the 800 pound gorilla of published computational chemistry anyway so you get reproducibility (of a sort) "for free."
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