On my rMBP, I did a quick back of the envelope comparison using PyPy 2.2.1 vs CPython 2.7.6 on OS X Mavericks and came up with (best of 3 runs): $ time pyp

On my rMBP, I did a quick back of the envelope comparison using PyPy 2.2.1 vs CPython 2.7.6 on OS X Mavericks and came up with (best of 3 runs): $ time pypy testcode.py real 0m1.529s user 0m1.402s sys 0m0.121s $ time python testcode.py real 0m13.880s user 0m13.635s sys 0m0.241s $ time python testcode_vectorized.py real 0m0.746s user 0m0.551s sys 0m0.139s