

Comparing Shed Skin to pypy is a apples to oranges comparison. However, comparing Shed Skin to rpython (the subset of python pypy is written in) is much more of a apples to apples comparison. In fact the restriction list of Shed Skin is almost exactly the same as the restriction list of rpython.
What you get with rpython however is some very insane optimizations. Where Shed Skin basically does Python to C++ translation, rpython will do deep introspection into the code, unrolling loops, inlining functions, ripping C structures apart (if you only use X out of {X, Y} why allocate space for Y?), and malloc removal. All this means that many times rpython can be faster than hand written C.
Also, the benchmarks shown in the link are from pypy 1.4...pypy 1.7 is the current version. And in one program I've see a speed boost of 5x just going from pypy 1.6 -> 1.7.
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And on top of all that, just because it's using a static compiler does not magically make it faster. There are several benchmarks where pypy actually out performs C code.
Edited 2012-01-16 14:28 UTC