How much faster is Python 2.7's new IO library compared to earlier versions?

Question

The Python 2.7 update note says:

A new version of the io library, rewritten in C for performance.

I've played with Python 2.7 a bit, but I don't see any performance gain:

>>> from timeit import Timer
>>> t = Timer('f = open("E:\\db.txt", "r"); f.read(); f.close()')
>>> t.timeit(10000)

And the result:

• Python 2.6.5 -- 12.879124022745913
• Python 2.7 -- 12.905614540395504

Am I doing it wrong?