I'll give that a try. I incorrectly stated arch type. Is i386, not x86.
Same thing in reality. x86 is a generic term that applies to i386, i486, i586, and i686. The default arch extension for most rpms on the x86 version of centos is i386. I'm not sure if there's a reason for this beyond legacy.
Likely yours isn't a true i386, as that was released around 1985, with a clockspeed of something between 16 and 33Mhz. If you have centos running on hardware that slow or that old, I want pictures! They'll make for excellent propaganda.