The optimization is great but for other servers and world configurations it leads to huge fps issues. Items like signs, item frames, and paintings do not "render out" anymore making them load more of these items causing fps issues. Servers with plot configurations suffer from this greatly since they are now loading in the item frames, signs, and paintings which were not previously loaded.

Suggested fix: revert the de-render to its previous state so all those items in the increased vicinity are not rendered causing lag.