Pickling, for one.<p><pre><code>  &gt;&gt;&gt; nt = namedtuple(&#x27;nt&#x27;, &#x27;a b&#x27;)
  &gt;&gt;&gt; nt10k = [nt(1, 2) for i in range(10000)]
  &gt;&gt;&gt; dict10k = [{&#x27;a&#x27;:1, &#x27;b&#x27;:2} for i in range(10000)]
  &gt;&gt;&gt; timeit pickle.dumps(nt10k)
  10 loops, best of 3: 26.3 ms per loop
  &gt;&gt;&gt; timeit pickle.dumps(dict10k)
  100 loops, best of 3: 2.49 ms per loop</code></pre>