Terrain using in incredible amount of memory what do I do?

Hello Developers,

Recently i have made posts on my game being super laggy for some odd reasons! And someone figured out there was A TON of memory being use like 4 - 5GB so today I decided to go digging myself to see what in the world was using so much memory and well I figured out it was believe it or not the terrain. The terrain voxels and physics were peaking over 1GB of memory just from those other things at most will peak up around 50 - 100MB So what should I do. Also, looking into it now I found another SINGLE THING using over 1.5GB i will send screenshots please help.

Other:
some other memory being use:

Thanks,
Cullis_WullisAlt

I have decided to delete the terrain and make my own with parts