Original graphic settings was everything on ultra (ever slider to the right).
There appears to be a random, but significant, drop in framerates when opening the map. It is not clear under which circumstances this will happen, but when it does the framerates will not recover on their own. I have been able to get framerates to stabilize again by going into the options and turning on/off v-sync to solve the issue. I have also tried changing the graphic options to use high/medium presets when this happens, and it works as well.