Server Ticking 1.13-pre

Server Ticking over 100000ms and 17,000 ticks leading to world unable to load or goes to a point where it crashes. Server does manage keep up after 7gb but break block delay seems to be there still CPU is a i7(on my brothers) and still doesn't like Minecraft new prelease. I do get crash logs when ever it ticks too long. And please fix the client it it goes from 3000 to 30 fps in a instant.