I've tried optimizing sympy and it's hard - there is a chance that it uses cython (which will slow things down on pypy) but also the gains were small (up to 2x) and only noticable if you run it for a while (at least few seconds).
SymPy is a bit of an example that while python as a language is not necesarilly slow, since you can make a plan for most parts, it breeds culture of unnecessary meta-programming, tons of copies and dict lookups that makes it REALLY HARD to optimize. ORMs go in the same category
I've tried optimizing sympy and it's hard - there is a chance that it uses cython (which will slow things down on pypy) but also the gains were small (up to 2x) and only noticable if you run it for a while (at least few seconds).
SymPy is a bit of an example that while python as a language is not necesarilly slow, since you can make a plan for most parts, it breeds culture of unnecessary meta-programming, tons of copies and dict lookups that makes it REALLY HARD to optimize. ORMs go in the same category