purpose of glibc-2.2.5-163.i686.rpm

As I was surfing through a FTP mirror of SuSE, I came across a file by the name of: glibc-2.2.5-163.i686.rpm The normal installation of SuSE 8.1 glibc compiled for i586, and it is under the i586 dir, not the i686 dir (obviously). I also noticed this file is on the SuSE CDs. So... what is it for? Having an i686 class CPU, should I install it? I'm expecting a speedup. Direct Link to RPM: ftp://ftp.gwdg.de/pub/suse/i386/8.1/suse/i686/glibc-2.2.5-163.i686.rpm -- Karol Pietrzak <noodlez84@earthlink.net> PGP KeyID: 3A1446A0