Hi Snoopy, >why so slow? You haven't provided sufficient information to assess why it runs so slow. I recommend that you compare the assembly of the subroutines generated by each compiler. Some questions that come to the fore: + Is VC6 generating 64-bit code? + Does the program constructed in such a way that takes advantage of a VC6 optimization that is not an optimization available to GCC 3.4? + What is the performance characteristics of the program when unoptimized with both compilers? HTH, --Eljay
