I disabled it. It was extremely laggy/freezy loading the world without it so it was hard to tell, but i don't believe it made a difference. It crashed after a bit for me.
This is not the same damn issue. I have a vanilla install on this same PC and it's not experiencing the same issues. I have a v7 install on this computer and its not experiencing the same issues. I have a v8.0.1 install on this computer it is experiencing these issues.
Several people have responded, i've linked to other threads, Velotican has seen other people reporting the issue. Please stop posting, you are contributing nothing productive to the thread and only getting in the way of actual progress.
I'm experiencing this exact issue as well, just like rikailp describes. It occurred on the transition from Mindcrack v7 to v8.01 and is not improved by adding or removing Optifine. My framerate also dropped from ~75 to ~30 in my main base. The rendering/fps issue doesn't seem as bad away from my processing equipment.
More on the lines of fps issues, I took a few screenshots.