the archive register function adds a member to an archive local table. Adding to this table and subsequent usage of the table during lookups might add some time to the serialization/de-serialization process. Then again it might not be significant - only experiment with a profiler could discern this. Actually I would have a greater concern. The sequence of archive register, and serialize statements have to be the same when loading as when the library was saved. If a subsequent version of your program adds an entry to the register.cpp file, then it won't match the information of stored in previously made archives. So they won't be readable. Addressing this would be possible, but also would require extra work. Robert Ramey -- View this message in context: http://boost.2283326.n4.nabble.com/serialization-slow-compile-times-with-arc... Sent from the Boost - Users mailing list archive at Nabble.com.