Hi, I have taken the task to replace a proprietary smart pointer (a fork of an earlier 'shared_ptr' variant) used in a library used for rendering of 3D scenes by the boost's current 'shared_ptr'. The reason is that I have found a couple of syntactic problems with the proprietary smart pointer that 'shared_ptr' doesn't have. While I succeeded syntactically, in certain performance tests the proprietary smart pointer performs about 20 times better than 'shared_ptr'. It seems that this is caused by the allocation of the use counter. For the proprietary smart pointer this allocation can be tweaked by passing allocators as template arguments, while 'shared_ptr' seems not to allow this. I have yet to find out what that performance difference means for real projects, but according to those familiar with the library the reason the allocators where introduced is that there's code that very extensively creates and destroys smart pointers which suffered badly from allocation costs. Is there a way for me to tweak 'shared_ptr's performance other than by again forking into a proprietary smart pointer and introducing allocators for that one? or is there any interest in the boost community for doing this? Thanks, Schobi