Hm I can't see the second image. It's says there is an error. No, I didn't join the meshes. That would make performance worse. I went into each mesh and removed duplicate vertices. If the terrain is all one big mesh the game will try to render the entire terrain which will result in poor performance.
Hi i tried it on the other map and it is fine it worked. I just had some shading issues but i guess i figured them out by clicking every option available and ctrl z-ing (what is a better way to learn than fucking around and finding out) so yeah lol thanks for giving that idea! it runs better than before on the same map although not by much on my case but it is more stable which i like so again thanks!!!