Let's say you have a good personal computer with these characteristics: i7-6700K, 32GB RAM, 256GB SSD, 2 x GTX 970 4GB And let's assume you can run your algorithms, software... for 24 hours. I wonder, if I would be calculating the orbital structure of an hydrogen atom with many electrons, What do you think it is the maximum number of electrons we could use to obtain an accurate prediction? In case we were calculating molecular properties, What do you think is the most complex structure we could simulate with those tools and amount of time? This is only to get an idea about what you can calculate at home without any supercomputer, so hopefully people with experience can tell aproximately were are the limits to personal computers. Thanks!!!!!!