A couple of years ago, I made the same exercise and, when benchmarking several real-world languages, I got similar results. On a slowish Intel CPU (from my memo

A couple of years ago, I made the same exercise and, when benchmarking several real-world languages, I got similar results. On a slowish Intel CPU (from my memory): DFA-based decoder: ~400 MB/s Naive decoder with ASCII: ~1.2 GB/s Naive decoder with with most Western languages: ~1.0 GB/s Naive decoder with with Russian, Chinese, Japanese: ~800 MB/s Branch prediction of modern CPUs is so good that it's hard to beat the naive if-else chain with real-world data. Interestingly, I got the worst performance with heavily accented Eastern European languages like Czech where performance dropped to 600-700 MB/s.