Why does up2date igonore rpms that I compile for my athlon, for update?

[VJ]

Hi,

I compile a few rpms from their src.rpm for athlon-xp architecture,
e.g. xorg. up2date ignores such rpms from up2date and does not even
show if there is any update available.

Why does it ignore the file if .athlon. is added to the name of the
rpm? Does recompiling change anything within RPMs also?

Regards from
VJ