On Jul 8, 2014, at 2:12 PM, Brett Viren <[email protected]> wrote: > Yasha Karant <[email protected]> writes: > >> how much additional RAM and hard drive space is required by this >> X86-64 implementation? > > The memory usage going from 32 to 64bit x86 really depends on the code > you run. My understanding is it boils down to how much of the job's > memory is made up of pointers as compared to other data types that are > invariant under this bit change. This can vary a lot and of course it > matters what the absolute memory usage is to begin with. If you are > concerned you should benchmark your actual code on both bit'isms. > > But, I can relate a few data points. > > The jobs we tend to run here are ~1-2GB to start with and I've seen ~50% > increase in memory usage for the same code complied in 32 and 64 bits. > These jobs come from relatively large C++ code bases and the code tends > to be written for functionality first and size optimization later (if > ever). I imagine they represent a, if maybe not the, worse case. >
Of course, you can still compile apps 32 bit if more appropriate for your needs.
