Obviously dumb microbenchmark, but here's ~17x on my machine:
$ time python -c 'sum(range(1_000_000_000))'
real 0m19.997s
user 0m19.992s
sys 0m0.005s
$ time pypy -c 'sum(range(1_000_000_000))'
real 0m1.146s
user 0m1.126s
sys 0m0.020s
I think some relatively simple math JITs and compiles nicely like that, but when you start using other parts of the language heavily like you would in a real project, it averages out to about ~4x due to the object, VM and locking model, I believe. It's been a while since I've looked into this.
