The json package is a lot slower than the simplejson package.  Both
packages have their C compiled speedup module; however:

  C:\>py26 -m timeit -s "from json import dumps, loads"
"loads(dumps(range(32)))"
  1000 loops, best of 3: 618 usec per loop

  C:\>py26 -m timeit -s "from simplejson import dumps, loads"
"loads(dumps(range(32)))"
  10000 loops, best of 3: 31 usec per loop

This is on Windows XP, with Python 2.6.2.