Are you serious? Of course you can. Some hash algorithms are slower than others, you can read that and know that. Allocating in a hot loop is probably slower than allocating outside of it. Duh? I can't believe this even has to be justified, of course you can look at code and get an idea of its performance properties lol

Obviously you want empirical evidence to justify changes, but like... duh, you can read code and understand how it executes.