Please use opencl

with extended heights it overloads 8 cpus I think you should use opencl 

to offload extra work as a gpu can handle 100s if not 1000s of threads if set up

https://feedback.minecraft.net/hc/en-us/community/posts/4425672970637-opencl-support

as lwgl can do that all it would need to be programmed so it could do that for world loading

and anything else it can

it would reduce the clock speed needed to run the game would be more stable

reachs 80 on 32 render