m4 is orders of magnitude slower (notice the different unit). If you write the Python script using bytes (not Unicode), then Python 3 is faster than Python 2,

m4 is orders of magnitude slower (notice the different unit). If you write the Python script using bytes (not Unicode), then Python 3 is faster than Python 2, at least for me. Python 3 is 20 % slower than GNU yes and Python 2 35 % slower than GNU yes. e: I think in your last sentence you are comparing results from different computers.