Ah, that's what you mean. Yeah, there's three types of Old Earth Relic: Two of them are: - +2 Yield in the Capital - +1 Other yield in all Cities (It's possible that in your version they still add bonuses towards the specific buildings, I later changed it to just add bonuses to the Infrastructure) They sound somewhat weak, but add up during the game, given that they also scale with %-modifiers. I find that for the most part I directly solve Old Earth Relics of good quality (and sometimes production/culture with lower quality), while keeping and combining low-quality artifacts. The third type adds +10% of one yield to all cities, but those bonuses will only start appearing once all of category 1+2 are used up, so in mass-artifact strategies (aka large focus on Early Exploration, mostly) it makes sense to combine as much as possible. Obviously I haven't done any theorycrafting, but from playing I feel that it makes sense to combine both methods, instead of just solving every single Old Earth Artifact. And overall Old Earth Artifacts are mostly meant to reward investment in early exploration, Alien Artifacts are mostly gathered over the course of the game if hostile towards aliens (and reward +Health and some other Bonuses) and Progenitor Artifacts still reward the same wonders they do in the base game, with some number changes. They're, aside from the few that you may pick up from Progenitor ruins early on, mostly gained by investing in certain virtues (not sure if they were already in the test version) and the moonbase.