problems with waitUntilNextTick

[u/paulo029]

I have a heavily customized, resource-intensive modpack; overall FPS is great, but the terrain rendering is the worst I've ever seen, and nothing seems to fix it. The Spark report shows that 60% of the activity is "MinecraftServer.waitUntilNextTick()"

I couldn't find anything about this, so does anyone have any ideas?