it's because the ruby implementation of "fasta" computes the entire result in memory and then prints it out; the lua one prints as it goes.

so, i'd take it with a huge slab of salt.

I'm sure, but luajit wins handily over all the scripting interpreters. I'm not much concerned with ruby in particular. I'm suspicious that luajit is constrained in features. I doubt you can dynamically load in object code for modules, for example. This makes it not quite a straightforward comparison to the other interpreters.