The Art of Computer Programming, volumes 1–3, was written in the late 1960s, with vol 3 finalized in Sept 1972 after a delay of “almost 3 years” because of rapid development of the subject matter.
I recall a statement (though I can’t find the actual page) where Knuth says 10! (About 3.6 million) separates the size of a problem that can be solved by brute force from those where such is impractical.
Now from Moore's Law, doubling every 18 months, I would estimate a modern computer would be faster by a factor of a billion. But, that seems to be an overestimate based on my benchmarks and surmising that it would have taken Knuth a matter of days to run.
Now Moore's law applies to equal cost, so comparing a major industrial machine against a desktop PC brings them closer together. Moore’s Law might not have started yet. Scale factors might be more complex— e.g. was I wasting power because I could have been manipulating 64-bit quantities and the problem only used 8?
So I wonder, just what were the performance characteristics of the kind of machine Knuth was familiar with at Princeton in the mid to late 1960s?