Python 2.6a3+ (trunk:64269M, Jun 14 2008, 11:36:56)
>>> util.memory()
5849088.0
>>> z = list(range(1000000))
>>> util.memory()
22380544.0
>>> del z
>>> util.memory()
17879040.0
Python 3.0a5+ (py3k:64080, Jun 10 2008, 18:22:21)
>>> util.memory()
9302016.0
>>> z = list(range(1000000))
>>> util.memory()
29011968.0
>>> del z
>>> util.memory()
9302016.0