Simple terrain causing massive lag?

I have a default terrain size of 1000 x 1000 but it’s causing lag, why is that?

Does the terrain have a built in LOD system for the terrain?

Note: There is nothing on the terrain besides hills that I painted.

sounds like a massive terrain.

you can change the settings of the terrain so its higher error number - could help a little.

main reason → i think its dependant on your machine specs tbh and in addition, the more detailed hills etc the slower it will be.

what is the specs of your machine?