Originally posted by MeaNGremmy:

More than likely it's an issue that the dev team hasn't got around to addressing yet, and will be smoothed out once proper optimising starts.

It does suck that terraforming and large scale building causes these problems, but hopefully once all the actual planned content is in the game the focus can shift to the performance side of things.

aye i really hope the devs'll Improve that, and are qualified for that...