[Python] Does PEP 412 make __slots__ redundant?

PEP 412, implemented in Python 3.3, introduces improved handling of attribute dictionaries, effectively reducing the memory footprint of class instances. __slots__ was designed for the same purpose, so is there any point in using __slots__ any more?

In an attempt to find out the answer myself, I run the following test, but the results don't make much sense:

class Slots(object):
__slots__ = ['a', 'b', 'c', 'd', 'e']
def __init__(self):
self.a = 1
self.b = 1
self.c = 1
self.d = 1
self.e = 1

class NoSlots(object):
def __init__(self):
self.a = 1
self.b = 1
self.c = 1
self.d = 1
self.e = 1


Python 3.3 Results:

>>> sys.getsizeof([Slots() for i in range(1000)])
Out[1]: 9024
>>> sys.getsizeof([NoSlots() for i in range(1000)])
Out[1]: 9024


Python 2.7 Results:

>>> sys.getsizeof([Slots() for i in range(1000)])
Out[1]: 4516
>>> sys.getsizeof([NoSlots() for i in range(1000)])
Out[1]: 4516


I would have expected the size to differ at least for Python 2.7, so I assume there is something wrong with the test.

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