Thanks for the report guys!
If you don`t mind it would really help us if you could try this:
1) Lower all visual settings to the lowest, restart the game (for setting to take effect) - and confirm if lag is the same?
2) Create a new town - does it lag as much?
3) And this is way more time consuming but could you please try installing the game using our own client and see if it helps with the lag?