CDK2309

ive just updated to 10.1 today. ive only played in single player mode. any new city i create in an existing region will lag every few seconds. the cities that existed in the region are not affected interestingly. ive tried restarting the computer as well. ive checked the task manager and performance stats and there are no other apps running hogging memory or anything. got 5 gigs free all the time. any way to undo the update and go back to 10.0?