This review only applies to the 1.12 version as I haven’t tried it on newer versions.

Clumps can significantly improve performance in situations where an area is generating lots of XP orbs, such as in mob farms. This is especially useful on servers. But this mod does it by replacing the XP entity, which can break mods that also rely on them. For this reason, if playing 1.12, you should use Fixeroo instead, which does the same thing without adding a new XP entity.