Comment # 4 on bug 1162283 from Jan Engelhardt

So RPM does not have a "i786" architecture, and though one can be added with a
little config, that is not helpful (i786 is not a thing, and neither is i586
actually, and it is unfortunate i586 has found its way into rpm���updated the
wiki pages). But there is "pentium4", albeit it's just an alias for the base
386 plus -march=. It does not enable SSE in its own right, so there is some
config to be done in either case.

Not only that, you would also have to teach zypper and OBS about the special
case that pentium4 is (similar to how i686 is used) and that zypper shall not
install a pentium4 rpm on a non-SSE2 machine (because rpm does not care what
you install).