Ive had something lagging my game down, currently am at ~10 settlements, spreaded a fair distance over the planet, avg. maybe 8 tiles between them. Development mode seems to indicate everytime the freezing lag is happening, the "Road Building Queue"-Algorithm is being executed. Guess I cant tell you more than that, Lag is pretty annoying and takes ~10 seconds to resolve, not sure if this issue resolves itself, will report back if I remember.