So VS11 is roughly 10% slower than VS10 for that test case. Can't say for sure why, but the fact that it is pre-release software as mentioned is likely to have something to do with it.

Thanks. Here VS11 is over 15% slower than VS10 with 5 million for input. The point about the pre-release software may have something to do with it, but I'd like to point out again that the numbers are reversed on the Ebenezer side -- the Ebenezer test with VS10 is over 20% slower than when built with VS11.

Obviously you're using different C++ language features and/or library functions. Boost tends to reach into the deeper, darker recesses of C++ metaprogramming, which while inherently fast, typically gets less developer time for optimizations.