Hi everybody, my first attempt to post to this list bounced, so I am trying again. My employer is an early adopter of the Boost Generic Geometry Library [GGL] in an engineering application related to mobile radio communicatons. We use it to estimate and optimize the coverage of 4G radio networks. Our code uses a lot of multi-polygon unions to estimate the amount of ground covered (and not covered) by radio beams and iteratively improves the antenna parameters. We've been compiling and shipping our application with Visual C++ 2008 so far. We found that GCC 4.4 on Linux was about 100% faster than Visual C++ 2008 on Linux without modifying the code. This bothered us quite a bit as both compilers were allowed to use full optimization. We found that by optimizing (globaly overloading) the new and delete operators to re-use allocated memory fragments on Windows we were able to get nearly 50% speed benefit, so we attributed much of the performance difference to sub-optimal memory heap management of Visual C++ 2008. Then we tried recompiling the project with Visual C++ 2010 Ultimate Release Candidate (RC). The speed gain of the algorithm was 900% (not joking) and the results still appear to be correct. Now this is surreal and no one here in the office has found a reasonable explanation yet without going into the metaphysical domain. Would anyone with knowledge of compiler and runtime internals be able to make an educated guess as to how such a speed gain of factor 10 is possible? Is anyone else seeing similar speedups in boost or in the geometry library when compiling with Visual C++ 2010 RC (HINT: it's a free download, so anyone can try it out until end of June 2010). Christian