Originally posted by Spanton:

Open the console (F5) and enter "optterrain"

if everything worked correctly, you will now see messages about how many tiles were optimized and repainted (or that no optimizable tiles were found).

FYI, this is not a map wide command so you'll have to go to the places you want to run the command, hope that helps. =)

Is there a special way to open it? Pressing F5 does nothing. F2 brings up some info stuff, but nothing I can type into. Also Thank you! I remember reading this somewhere.