Should I install x86_64 or i386 RPM packages? [closed]

In this case, use the i386 (or 32-bit) package.

A quick overview of architecture names for x86 systems:

• i386: The 80386 CPU has historically been the bare minimum for running Linux on a PC-compatible system. Consequently, a package for "i386" is designed for maximum compatibility and can run on any x86-like system; a system that describes itself as "i386" is either ancient or exotic, and can only be counted on to run i386 packages.
• i485, i586: Rarely-seen, these refer to the 80486 and Pentium (80586) CPUs. Almost nobody builds packages specifically for them, targeting either i386 or i686 instead.
• i686: This is the "P6" microarchitecture, used by Intel for the Pentium Pro and newer. It's generally considered the baseline for "modern" 32-bit x86 systems. An "i686" package is designed to run on these systems (and will usually perform better than a "i386" version); an "i686" system can run any i386, i486, i586, or i686 package.
• x86_64: This is the 64-bit instruction set for x86 CPUs. An "x86_64" package can only run on x86_64 systems; an "x86_64" system requires special kernel and library support (which almost all mainstream Linux distros provide) to run packages from the i*86 family.

You've got an "i686" system, so given the choice between "i386" and "x86_64", you want the "i386" version.

You can simply use the "arch" command in order to have your answer.

You need the 32-bit (i.e. the i386) package as the "i686" report shows that you're running a 32-bit platform.

As a general rule, if you're not sure of the destination platform, get the 32-bit build, as a 64-bit platform can run a 32-bit image, but not the other way around.