Run python script in PyPy

I have a python script developed in Spyder using Python 2.7.4.
This script is called from another python script using:

execfile('script.py')

I’d like to know how can I run both python scripts using PyPy (I’d like this because it is faster than standard Python). Thanks!

P.S.: I’ve already installed PyPy in Windows.

Run the first Python script using pypy scriptname.py on the command line. The code run by execfile() will also be run in PyPy, because the main script (execfile()) is being run in PyPy.