Sudden lag-spike followed by crash...out of order!

What I expected to happen was...:
I expected everything to work out just fine. But that only lasted until the sudden lag spike of death showed up.

What actually happened was...:
I was just running around, minding my own business getting resourses for my builds, then suddely i crashed while changeing the render distance. because i didn't need such a big render distance while building.

Steps to Reproduce:
1. First, you run a little around.
2. then you change your render distance to something random, and continiue running around, and bam! crash