These archives are for those who don't like auto setup. You can manually install XviD codecs and filter.
These files are latest cvs builds(cvs.xvid.org), so they may be unstable beta version. Only those who want to try latest XviD should use them.
There are two archives. One is optimized for Pentium-II or later, the other is for Pentium-4 (or later?). The difference is optimization by VS.NET2003 compiler. I don't know whether the performance is really different or not.