Performance optimization has come up recently but I had avoided posting anything to the list as it is not exactly a boost specific topic. However, John has suggested that gcc produces slower boost results due to lack of inlining. In a quick test on some of my own code, I couldn't find any evidence of that. Further, most of the discussion here seems to center on things like instruction count. As someone who learned to program on an 8080, I have a lot of sympathy but I was shocked to learn in this century (quite literally true for myself) that there are a lot of additional factors that effect performance on today's architectures. Interested parties may wish to look at things like this: ftp://download.intel.com/design/Pentium4/papers/24943801.pdf In particular, after skimming the memory hierachy, consider also the specific FPU you are using. I know in one case, a functioning audio codec was having noticeable speed problems visible on task manager. Further investigation found perceptibly irrelevant things like near-zero values or NAN/ overlfow problems that didn't effect the final results. My point here is that even a few denormals or exceptional cases can have a big impact on performance- you could have these even if your output looks right. Certainly vectorized code would help but if the memory access patterns are wrong these will limit performance- it can be hard to keep one execution unit busy with slow memory. Just some things to think about if you care. Mike Marchywka 586 Saint James Walk Marietta GA 30067-7165 404-788-1216 (C)<- leave message 989-348-4796 (P)<- emergency only marchywka@hotmail.com Note: Hotmail is blocking my mom's entire ISP claiming it is to reduce spam but probably to force users to use hotmail. Please DON'T assume I am ignoring you and try me on marchywka@yahoo.com if no reply here. Thanks. _________________________________________________________________ Put your friends on the big screen with Windows Vista® + Windows Live™. http://www.microsoft.com/windows/shop/specialoffers.mspx?ocid=TXT_TAGLM_CPC_...