From FreeBSD lists :
The second Release Candidate for FreeBSD 6.4 is now available. FreeBSD
6.4-RC2 should be the last of the public test builds for the FreeBSD 6.4
release cycle. Unless a big show-stopper is found from this round of
testing we should begin the 6.4-RELEASE builds in about a week and a
half. We encourage you to test out 6.4-RC2 and report any problems by
submitting PRs or via email to the freebsd-stable list.One of the things that could use some testing is the late-arriving
patches to sysinstall that should eliminate the excessive disc swapping
that previous releases had if things like gnome or kde were installed as
part of the initial CDROM install. Things selected before you reach the
“Package Selection Menu” are handled as separate passes from the things
that get selected at that menu. So depending on what you install before
you reach that menu (e.g. Xorg selected as part of the distributions)
and what you select at that menu there may still be some disc swapping
involved. But “worst case” given the current layout it should ask for
any given disc no more than twice.