Dreadwyrm > Perfect Zodiac > Augmented Ironworks > Ironworks > Perfect Nexus > High Allagan > Diamond > etc.

Zodiac is marginally better than augmented ironworks because it has so little det and skillspeed is a dps loss, so the crit and det on relic can make up the lost weapon damage. If you aren't going to bother making your relic perfect then there is basically no reason to use it at all outside of a placeholder weapon for getting diamond, rosenbogen, or HA because it won't have those great secondary stats to put it above the other weapons in its ilvl tier.